Convert.ToByte 方法

定义

将指定的值转换为 8 位无符号整数。Converts a specified value to an 8-bit unsigned integer.

重载

ToByte(String)

将数字的指定字符串表示形式转换为等效的 8 位无符号整数。Converts the specified string representation of a number to an equivalent 8-bit unsigned integer.

ToByte(UInt16)

将指定的 16 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 16-bit unsigned integer to an equivalent 8-bit unsigned integer.

ToByte(UInt32)

将指定的 32 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 8-bit unsigned integer.

ToByte(String, Int32)

将指定基数的数字的字符串表示形式转换为等效的 8 位无符号整数。Converts the string representation of a number in a specified base to an equivalent 8-bit unsigned integer.

ToByte(Object, IFormatProvider)

使用指定的区域性特定格式设置信息,将指定对象的值转换为 8 位无符号整数。Converts the value of the specified object to an 8-bit unsigned integer, using the specified culture-specific formatting information.

ToByte(String, IFormatProvider)

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 8 位无符号整数。Converts the specified string representation of a number to an equivalent 8-bit unsigned integer, using specified culture-specific formatting information.

ToByte(Single)

将指定的单精度浮点数的值转换为等效的 8 位无符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 8-bit unsigned integer.

ToByte(UInt64)

将指定的 64 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 8-bit unsigned integer.

ToByte(SByte)

将指定的 8 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 8-bit signed integer to an equivalent 8-bit unsigned integer.

ToByte(Decimal)

将指定的十进制数的值转换为等效的 8 位无符号整数。Converts the value of the specified decimal number to an equivalent 8-bit unsigned integer.

ToByte(Int64)

将指定的 64 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 8-bit unsigned integer.

ToByte(Byte)

返回指定的 8 位无符号整数;不执行任何实际的转换。Returns the specified 8-bit unsigned integer; no actual conversion is performed.

ToByte(Char)

将指定 Unicode 字符的值转换为等效的 8 位无符号整数。Converts the value of the specified Unicode character to the equivalent 8-bit unsigned integer.

ToByte(DateTime)

调用此方法始终引发 InvalidCastExceptionCalling this method always throws InvalidCastException.

ToByte(Boolean)

将指定的布尔值转换为等效的 8 位无符号整数。Converts the specified Boolean value to the equivalent 8-bit unsigned integer.

ToByte(Double)

将指定的双精度浮点数的值转换为等效的 8 位无符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 8-bit unsigned integer.

ToByte(Int16)

将指定的 16 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 16-bit signed integer to an equivalent 8-bit unsigned integer.

ToByte(Int32)

将指定的 32 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 32-bit signed integer to an equivalent 8-bit unsigned integer.

ToByte(Object)

将指定对象的值转换为 8 位无符号整数。Converts the value of the specified object to an 8-bit unsigned integer.

ToByte(String)

将数字的指定字符串表示形式转换为等效的 8 位无符号整数。Converts the specified string representation of a number to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::String ^ value);
public static byte ToByte (string value);
public static byte ToByte (string? value);
static member ToByte : string -> byte
Public Shared Function ToByte (value As String) As Byte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数,如果 valuenull,则为零。An 8-bit unsigned integer that is equivalent to value, or zero if value is null.

例外

value 不由一个可选符号后跟一系列数字 (0-9) 组成。value does not consist of an optional sign followed by a sequence of digits (0 through 9).

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例定义一个字符串数组,并尝试将每个字符串转换为 ByteThe following example defines a string array and attempts to convert each string to a Byte. 请注意,当 null 字符串分析为零时,将 String.Empty 引发 FormatExceptionNote that while a null string parses to zero, String.Empty throws a FormatException. 另请注意,在前导空格和尾随空格分析成功后,格式符号(如货币符号、组分隔符或小数分隔符)不会。Also note that while leading and trailing spaces parse successfully, formatting symbols, such as currency symbols, group separators, or decimal separators, do not.

using System;

public class Example
{
   public static void Main()
   {
      String[] values = { null, "", "0xC9", "C9", "101", "16.3",
                          "$12", "$12.01", "-4", "1,032", "255",
                          "   16  " };
      foreach (var value in values) {
         try {
            byte number = Convert.ToByte(value);
            Console.WriteLine("'{0}' --> {1}",
                              value == null ? "<null>" : value, number);
         }
         catch (FormatException) {
            Console.WriteLine("Bad Format: '{0}'",
                              value == null ? "<null>" : value);
         }
         catch (OverflowException) {
            Console.WriteLine("OverflowException: '{0}'", value);
         }
      }
   }
}
// The example displays the following output:
//     '<null>' --> 0
//     Bad Format: ''
//     Bad Format: '0xC9'
//     Bad Format: 'C9'
//     '101' --> 101
//     Bad Format: '16.3'
//     Bad Format: '$12'
//     Bad Format: '$12.01'
//     OverflowException: '-4'
//     Bad Format: '1,032'
//     '255' --> 255
//     '   16  ' --> 16
Module Example
   Public Sub Main()
      Dim values() As String = { Nothing, "", "0xC9", "C9", "101", 
                                 "16.3", "$12", "$12.01", "-4", 
                                 "1,032", "255", "   16  " }
      For Each value In values
         Try 
            Dim number As Byte = Convert.ToByte(value)
            Console.WriteLine("'{0}' --> {1}", 
                              If(value Is Nothing, "<null>", value), number)
         Catch e As FormatException
            Console.WriteLine("Bad Format: '{0}'", 
                              If(value Is Nothing, "<null>", value))
         Catch e As OverflowException
            Console.WriteLine("OverflowException: '{0}'", value)
         End Try
      Next
   End Sub
End Module
' The example displays the following output:
'     '<null>' --> 0
'     Bad Format: ''
'     Bad Format: '0xC9'
'     Bad Format: 'C9'
'     '101' --> 101
'     Bad Format: '16.3'
'     Bad Format: '$12'
'     Bad Format: '$12.01'
'     OverflowException: '-4'
'     Bad Format: '1,032'
'     '255' --> 255
'     '   16  ' --> 16

注解

使用 ToByte(String) 方法等效于传递 valueByte.Parse(String) 方法。Using the ToByte(String) method is equivalent to passing value to the Byte.Parse(String) method. 使用当前线程区域性的格式设置约定解释 valuevalue is interpreted by using the formatting conventions of the current thread culture.

如果你不希望在转换失败时处理异常,则可以改为调用 Byte.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Byte.TryParse method instead. 它将返回一个 Boolean 值,该值指示转换是成功还是失败。It returns a Boolean value that indicates whether the conversion succeeded or failed.

另请参阅

适用于

ToByte(UInt16)

重要

此 API 不符合 CLS。

将指定的 16 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 16-bit unsigned integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::UInt16 value);
[System.CLSCompliant(false)]
public static byte ToByte (ushort value);
[<System.CLSCompliant(false)>]
static member ToByte : uint16 -> byte
Public Shared Function ToByte (value As UShort) As Byte

参数

value
UInt16

要转换的 16 位无符号整数。The 16-bit unsigned integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

属性

例外

value 大于 MaxValuevalue is greater than MaxValue.

示例

下面的示例将一个无符号16位整数数组转换为 Byte 值。The following example converts an array of unsigned 16-bit integers to Byte values.

ushort[] numbers = { UInt16.MinValue, 121, 340, UInt16.MaxValue };
byte result;
foreach (ushort number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt16 value 0 to the Byte value 0.
//       Converted the UInt16 value 121 to the Byte value 121.
//       The UInt16 value 340 is outside the range of the Byte type.
//       The UInt16 value 65535 is outside the range of the Byte type.
Dim numbers() As UShort = { UInt16.MinValue, 121, 340, UInt16.MaxValue }
Dim result As Byte
For Each number As UShort In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt16 value 0 to the Byte value 0.
'       Converted the UInt16 value 121 to the Byte value 121.
'       The UInt16 value 340 is outside the range of the Byte type.
'       The UInt16 value 65535 is outside the range of the Byte type.

适用于

ToByte(UInt32)

重要

此 API 不符合 CLS。

将指定的 32 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 32-bit unsigned integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::UInt32 value);
[System.CLSCompliant(false)]
public static byte ToByte (uint value);
[<System.CLSCompliant(false)>]
static member ToByte : uint32 -> byte
Public Shared Function ToByte (value As UInteger) As Byte

参数

value
UInt32

要转换的 32 位无符号整数。The 32-bit unsigned integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

属性

例外

value 大于 MaxValuevalue is greater than MaxValue.

示例

下面的示例将无符号整数的数组转换为 Byte 值。The following example converts an array of unsigned integers to Byte values.

uint[] numbers = { UInt32.MinValue, 121, 340, UInt32.MaxValue };
byte result;
foreach (uint number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt32 value 0 to the Byte value 0.
//       Converted the UInt32 value 121 to the Byte value 121.
//       The UInt32 value 340 is outside the range of the Byte type.
//       The UInt32 value 4294967295 is outside the range of the Byte type.
Dim numbers() As UInteger = { UInt32.MinValue, 121, 340, UInt32.MaxValue }
Dim result As Byte
For Each number As UInteger In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt32 value 0 to the Byte value 0.
'       Converted the UInt32 value 121 to the Byte value 121.
'       The UInt32 value 340 is outside the range of the Byte type.
'       The UInt32 value 4294967295 is outside the range of the Byte type.

适用于

ToByte(String, Int32)

将指定基数的数字的字符串表示形式转换为等效的 8 位无符号整数。Converts the string representation of a number in a specified base to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::String ^ value, int fromBase);
public static byte ToByte (string value, int fromBase);
public static byte ToByte (string? value, int fromBase);
static member ToByte : string * int -> byte
Public Shared Function ToByte (value As String, fromBase As Integer) As Byte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

fromBase
Int32

value 中数字的基数,它必须是 2、8、10 或 16。The base of the number in value, which must be 2, 8, 10, or 16.

返回

Byte

value 中数字等效的 8 位无符号整数,如果 valuenull,则为 0(零)。An 8-bit unsigned integer that is equivalent to the number in value, or 0 (zero) if value is null.

例外

fromBase 不是 2、8、10 或 16。fromBase is not 2, 8, 10, or 16.

-or-

value(表示非 10 为基数的无符号数字)的前面带一个负号。value, which represents a non-base 10 unsigned number, is prefixed with a negative sign.

valueEmptyvalue is Empty.

value 包含一个字符,该字符不是由 fromBase 指定的基数中的有效数字。value contains a character that is not a valid digit in the base specified by fromBase. 如果 value 中的第一个字符无效,则该异常消息指示没有要转换的数字;否则,该消息指示 value 包含无效的尾随字符。The exception message indicates that there are no digits to convert if the first character in value is invalid; otherwise, the message indicates that value contains invalid trailing characters.

value(表示 10 为基的无符号数字)的前面带一个负号。value, which represents a base 10 unsigned number, is prefixed with a negative sign.

-or-

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例交替尝试将字符串数组解释为二进制、八进制、十进制和十六进制值的表示形式。The following example alternately attempts to interpret an array of strings as the representation of binary, octal, decimal, and hexadecimal values.

using System;

public class Example
{
   public static void Main()
   {
      int[] bases = { 2, 8, 10, 16 };
      string[] values = { "-1", "1", "08", "0F", "11" , "12", "30",
                          "101", "255", "FF", "10000000", "80" };
      byte number;
      foreach (int numBase in bases)
      {
         Console.WriteLine("Base {0}:", numBase);
         foreach (string value in values)
         {
            try {
               number = Convert.ToByte(value, numBase);
               Console.WriteLine("   Converted '{0}' to {1}.", value, number);
            }
            catch (FormatException) {
               Console.WriteLine("   '{0}' is not in the correct format for a base {1} byte value.",
                                 value, numBase);
            }
            catch (OverflowException) {
               Console.WriteLine("   '{0}' is outside the range of the Byte type.", value);
            }
            catch (ArgumentException) {
               Console.WriteLine("   '{0}' is invalid in base {1}.", value, numBase);
            }
         }
      }
   }
}
// The example displays the following output:
//    Base 2:
//       '-1' is invalid in base 2.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 2 conversion.
//       '0F' is not in the correct format for a base 2 conversion.
//       Converted '11' to 3.
//       '12' is not in the correct format for a base 2 conversion.
//       '30' is not in the correct format for a base 2 conversion.
//       Converted '101' to 5.
//       '255' is not in the correct format for a base 2 conversion.
//       'FF' is not in the correct format for a base 2 conversion.
//       Converted '10000000' to 128.
//       '80' is not in the correct format for a base 2 conversion.
//    Base 8:
//       '-1' is invalid in base 8.
//       Converted '1' to 1.
//       '08' is not in the correct format for a base 8 conversion.
//       '0F' is not in the correct format for a base 8 conversion.
//       Converted '11' to 9.
//       Converted '12' to 10.
//       Converted '30' to 24.
//       Converted '101' to 65.
//       Converted '255' to 173.
//       'FF' is not in the correct format for a base 8 conversion.
//       '10000000' is outside the range of the Byte type.
//       '80' is not in the correct format for a base 8 conversion.
//    Base 10:
//       '-1' is outside the range of the Byte type.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       '0F' is not in the correct format for a base 10 conversion.
//       Converted '11' to 11.
//       Converted '12' to 12.
//       Converted '30' to 30.
//       Converted '101' to 101.
//       Converted '255' to 255.
//       'FF' is not in the correct format for a base 10 conversion.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 80.
//    Base 16:
//       '-1' is invalid in base 16.
//       Converted '1' to 1.
//       Converted '08' to 8.
//       Converted '0F' to 15.
//       Converted '11' to 17.
//       Converted '12' to 18.
//       Converted '30' to 48.
//       '101' is outside the range of the Byte type.
//       '255' is outside the range of the Byte type.
//       Converted 'FF' to 255.
//       '10000000' is outside the range of the Byte type.
//       Converted '80' to 128.
Module Example
   Public Sub Main()
      Dim bases() As Integer = { 2, 8, 10, 16 }
      Dim values() As String = { "-1", "1", "08", "0F", "11" , "12", "30", _                
                                  "101", "255", "FF", "10000000", "80" }
      Dim number As Byte
      For Each base As Integer In bases
         Console.WriteLine("Base {0}:", base)
         For Each value As String In values
            Try
               number = Convert.ToByte(value, base)
               Console.WriteLine("   Converted '{0}' to {1}.", value, number)
            Catch e As FormatException
               Console.WriteLine("   '{0}' is not in the correct format for a base {1} conversion.", _
                                 value, base)
            Catch e As OverflowException
               Console.WriteLine("   '{0}' is outside the range of the Byte type.", value)
            Catch e As ArgumentException
               Console.WriteLine("   '{0}' is invalid in base {1}.", value, base)
            End Try   
         Next                                 
      Next 
   End Sub
End Module
' The example displays the following output:
'    Base 2:
'       '-1' is invalid in base 2.
'       Converted '1' to 1.
'       '08' is not in the correct format for a base 2 conversion.
'       '0F' is not in the correct format for a base 2 conversion.
'       Converted '11' to 3.
'       '12' is not in the correct format for a base 2 conversion.
'       '30' is not in the correct format for a base 2 conversion.
'       Converted '101' to 5.
'       '255' is not in the correct format for a base 2 conversion.
'       'FF' is not in the correct format for a base 2 conversion.
'       Converted '10000000' to 128.
'       '80' is not in the correct format for a base 2 conversion.
'    Base 8:
'       '-1' is invalid in base 8.
'       Converted '1' to 1.
'       '08' is not in the correct format for a base 8 conversion.
'       '0F' is not in the correct format for a base 8 conversion.
'       Converted '11' to 9.
'       Converted '12' to 10.
'       Converted '30' to 24.
'       Converted '101' to 65.
'       Converted '255' to 173.
'       'FF' is not in the correct format for a base 8 conversion.
'       '10000000' is outside the range of the Byte type.
'       '80' is not in the correct format for a base 8 conversion.
'    Base 10:
'       '-1' is outside the range of the Byte type.
'       Converted '1' to 1.
'       Converted '08' to 8.
'       '0F' is not in the correct format for a base 10 conversion.
'       Converted '11' to 11.
'       Converted '12' to 12.
'       Converted '30' to 30.
'       Converted '101' to 101.
'       Converted '255' to 255.
'       'FF' is not in the correct format for a base 10 conversion.
'       '10000000' is outside the range of the Byte type.
'       Converted '80' to 80.
'    Base 16:
'       '-1' is invalid in base 16.
'       Converted '1' to 1.
'       Converted '08' to 8.
'       Converted '0F' to 15.
'       Converted '11' to 17.
'       Converted '12' to 18.
'       Converted '30' to 48.
'       '101' is outside the range of the Byte type.
'       '255' is outside the range of the Byte type.
'       Converted 'FF' to 255.
'       '10000000' is outside the range of the Byte type.
'       Converted '80' to 128.

注解

如果 fromBase 为16,则可以为参数指定的数字加上 value "0x" 或 "0x" 作为前缀。If fromBase is 16, you can prefix the number specified by the value parameter with "0x" or "0X".

由于 Byte 数据类型仅支持无符号值,因此该 ToByte(String, Int32) 方法假定 value 使用无符号二进制表示形式表示。Because the Byte data type supports unsigned values only, the ToByte(String, Int32) method assumes that value is expressed using unsigned binary representation. 换句话说,所有八位都用来表示数值,并且不存在符号位。In other words, all eight bits are used to represent the numeric value, and a sign bit is absent. 因此,可以编写代码,在此代码中,如果有符号字节值超出了数据类型的范围,则会 Byte 将其转换为一个 Byte 值,而方法不会引发异常。As a result, it is possible to write code in which a signed byte value that is out of the range of the Byte data type is converted to a Byte value without the method throwing an exception. 下面的示例将转换 MinValue 为其十六进制字符串表示形式,然后调用 ToByte(String, Int32) 方法。The following example converts MinValue to its hexadecimal string representation, and then calls the ToByte(String, Int32) method. 方法会显示消息 "0x80 转换为 128",而不是引发异常。Instead of throwing an exception, the method displays the message, "0x80 converts to 128."

// Create a hexadecimal value out of range of the Byte type.
string value = SByte.MinValue.ToString("X");
// Convert it back to a number.
try
{
   byte number = Convert.ToByte(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a byte.", value);
}
' Create a hexadecimal value out of range of the Byte type.
Dim value As String = SByte.MinValue.ToString("X")
' Convert it back to a number.
Try
   Dim number As Byte = Convert.ToByte(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a byte.", value)
End Try   

执行二元运算或数值转换时,开发人员始终负责验证方法或运算符是否使用适当的数值表示形式来解释特定值。When performing binary operations or numeric conversions, it is always the responsibility of the developer to verify that a method or operator is using the appropriate numeric representation to interpret a particular value. 下面的示例演示了一种方法,用于确保方法在将十六进制字符串表示形式转换为值时不会对其进行不当使用 ByteThe following example illustrates one technique for ensuring that the method does not inappropriately use unsigned binary representation when it converts a hexadecimal string representation to a Byte value. 该示例在将值转换为其字符串表示形式时,确定某个值是否表示有符号或无符号整数。The example determines whether a value represents a signed or an unsigned integer while it is converting that value to its string representation. 当示例将该值转换回某个值时 Byte ,它会检查原始值是否为有符号整数。When the example converts the value back to a Byte value, it checks whether the original value was a signed integer. 如果是这样,并设置了其高序位 (这表示该值为负数,并且它使用两个反码表示形式,而不是未签名的二进制表示形式) ,则该方法将引发异常。If so, and if its high-order bit is set (which indicates that the value is negative and that it uses two's complement instead of unsigned binary representation), the method throws an exception.

// Create a negative hexadecimal value out of range of the Byte type.
sbyte sourceNumber = SByte.MinValue;
bool isSigned = Math.Sign((sbyte)sourceNumber.GetType().GetField("MinValue").GetValue(null)) == -1;
string value = sourceNumber.ToString("X");
byte targetNumber;
try
{
   targetNumber = Convert.ToByte(value, 16);
   if (isSigned && ((targetNumber & 0x80) != 0))
      throw new OverflowException();
   else
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to an unsigned byte.", value);
}
// Displays the following to the console:
//    Unable to convert '0x80' to an unsigned byte.
' Create a negative hexadecimal value out of range of the Byte type.
Dim sourceNumber As SByte = SByte.MinValue
Dim isSigned As Boolean = Math.Sign(sourceNumber.MinValue) = -1
Dim value As String = sourceNumber.ToString("X")
Dim targetNumber As Byte
Try
   targetNumber = Convert.ToByte(value, 16)
   If isSigned And ((targetNumber And &H80) <> 0) Then
      Throw New OverflowException()
   Else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber)
   End If    
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to an unsigned byte.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0x80' to an unsigned byte.     

适用于

ToByte(Object, IFormatProvider)

使用指定的区域性特定格式设置信息,将指定对象的值转换为 8 位无符号整数。Converts the value of the specified object to an 8-bit unsigned integer, using the specified culture-specific formatting information.

public:
 static System::Byte ToByte(System::Object ^ value, IFormatProvider ^ provider);
public static byte ToByte (object value, IFormatProvider provider);
public static byte ToByte (object? value, IFormatProvider? provider);
static member ToByte : obj * IFormatProvider -> byte
Public Shared Function ToByte (value As Object, provider As IFormatProvider) As Byte

参数

value
Object

一个实现 IConvertible 接口的对象。An object that implements the IConvertible interface.

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。An object that supplies culture-specific formatting information.

返回

Byte

一个与 value 等效的 8 位无符号整数,如果 valuenull,则为零。An 8-bit unsigned integer that is equivalent to value, or zero if value is null.

例外

value 未采用 Byte 值的属性格式。value is not in the property format for a Byte value.

value 不实现 IConvertiblevalue does not implement IConvertible.

-or-

不支持从 value 转换为 Byte 类型。Conversion from value to the Byte type is not supported.

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例定义一个实现 ByteString 接口的 IConvertible 类。The following example defines a ByteString class that implements the IConvertible interface. 类存储字节值的字符串表示形式和符号字段,使其能够表示有符号和无符号的字节值。The class stores the string representation of a byte value along with a sign field, so that it is able to represent both signed and unsigned byte values.

using System;
using System.Globalization;

public enum SignBit { Negative=-1, Zero=0, Positive=1 };

public struct ByteString : IConvertible
{
   private SignBit signBit;
   private string byteString;

   public SignBit Sign
   {
      set { signBit = value; }
      get { return signBit; }
   }

   public string Value
   {
      set {
         if (value.Trim().Length > 2)
            throw new ArgumentException("The string representation of a byte cannot have more than two characters.");
         else
            byteString = value;
      }
      get { return byteString; }
   }

   // IConvertible implementations.
   public TypeCode GetTypeCode() {
      return TypeCode.Object;
   }

   public bool ToBoolean(IFormatProvider provider)
   {
      if (signBit == SignBit.Zero)
         return false;
      else
         return true;
   }

   public byte ToByte(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16)));
      else
         return Byte.Parse(byteString, NumberStyles.HexNumber);
   }

   public char ToChar(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative) {
         throw new OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)));
      }
      else {
         byte byteValue = Byte.Parse(this.byteString, NumberStyles.HexNumber);
         return Convert.ToChar(byteValue);
      }
   }

   public DateTime ToDateTime(IFormatProvider provider)
   {
      throw new InvalidCastException("ByteString to DateTime conversion is not supported.");
   }

   public decimal ToDecimal(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
      {
         sbyte byteValue = SByte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
      else
      {
         byte byteValue = Byte.Parse(byteString, NumberStyles.HexNumber);
         return Convert.ToDecimal(byteValue);
      }
   }

   public double ToDouble(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public short ToInt16(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public int ToInt32(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public long ToInt64(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public sbyte ToSByte(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         try {
            return Convert.ToSByte(Byte.Parse(byteString, NumberStyles.HexNumber));
         }
         catch (OverflowException e) {
            throw new OverflowException(String.Format("{0} is outside the range of the SByte type.",
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)), e);
         }
      else
         return SByte.Parse(byteString, NumberStyles.HexNumber);
   }

   public float ToSingle(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber));
      else
         return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public string ToString(IFormatProvider provider)
   {
      return "0x" + this.byteString;
   }

   public object ToType(Type conversionType, IFormatProvider provider)
   {
      switch (Type.GetTypeCode(conversionType))
      {
         case TypeCode.Boolean:
            return this.ToBoolean(null);
         case TypeCode.Byte:
            return this.ToByte(null);
         case TypeCode.Char:
            return this.ToChar(null);
         case TypeCode.DateTime:
            return this.ToDateTime(null);
         case TypeCode.Decimal:
            return this.ToDecimal(null);
         case TypeCode.Double:
            return this.ToDouble(null);
         case TypeCode.Int16:
            return this.ToInt16(null);
         case TypeCode.Int32:
            return this.ToInt32(null);
         case TypeCode.Int64:
            return this.ToInt64(null);
         case TypeCode.Object:
            if (typeof(ByteString).Equals(conversionType))
               return this;
            else
               throw new InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name));
         case TypeCode.SByte:
            return this.ToSByte(null);
         case TypeCode.Single:
            return this.ToSingle(null);
         case TypeCode.String:
            return this.ToString(null);
         case TypeCode.UInt16:
            return this.ToUInt16(null);
         case TypeCode.UInt32:
            return this.ToUInt32(null);
         case TypeCode.UInt64:
            return this.ToUInt64(null);
         default:
            throw new InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name));
      }
   }

   public UInt16 ToUInt16(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt16 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public UInt32 ToUInt32(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt32 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber));
   }

   public UInt64 ToUInt64(IFormatProvider provider)
   {
      if (signBit == SignBit.Negative)
         throw new OverflowException(String.Format("{0} is outside the range of the UInt64 type.",
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)));
      else
         return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber));
   }
}
Imports System.Globalization

Public Enum SignBit As Integer
   Positive = 1
   Zero = 0
   Negative = -1
End Enum

Public Structure ByteString : Implements IConvertible
   Private signBit As SignBit
   Private byteString As String
   
   Public Property Sign As SignBit
      Set
         signBit = value
      End Set
      Get
         Return signBit
      End Get
   End Property
   
   Public Property Value As String
      Set
         If value.Trim().Length > 2 Then
            Throw New ArgumentException("The string representation of a byte cannot have more than two characters.")
         Else
            byteString = value
         End If   
      End Set
      Get
         Return byteString
      End Get
   End Property
   
   ' IConvertible implementations.
   Public Function GetTypeCode() As TypeCode _
                   Implements IConvertible.GetTypeCode
      Return TypeCode.Object
   End Function
   
   Public Function ToBoolean(provider As IFormatProvider) As Boolean _
                   Implements IConvertible.ToBoolean
      If signBit = SignBit.Zero Then
         Return False
      Else
         Return True
      End If
   End Function 
   
   Public Function ToByte(provider As IFormatProvider) As Byte _
                   Implements IConvertible.ToByte
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is out of range of the Byte type.", Convert.ToSByte(byteString, 16))) 
      Else
         Return Byte.Parse(byteString, NumberStyles.HexNumber)
      End If       
   End Function
   
   Public Function ToChar(provider As IFormatProvider) As Char _
                   Implements IConvertible.ToChar
      If signBit = signBit.Negative Then 
         Throw New OverflowException(String.Format("{0} is out of range of the Char type.", Convert.ToSByte(byteString, 16)))
      Else
         Dim byteValue As Byte = Byte.Parse(Me.byteString, NumberStyles.HexNumber)
         Return Convert.ToChar(byteValue)
      End If                
   End Function 
   
   Public Function ToDateTime(provider As IFormatProvider) As Date _
                   Implements IConvertible.ToDateTime
      Throw New InvalidCastException("ByteString to DateTime conversion is not supported.")
   End Function
   
   Public Function ToDecimal(provider As IFormatProvider) As Decimal _
                   Implements IConvertible.ToDecimal
      If signBit = signBit.Negative Then
         Dim byteValue As SByte = SByte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      Else
         Dim byteValue As Byte = Byte.Parse(byteString, NumberStyles.HexNumber)
         Return Convert.ToDecimal(byteValue)
      End If
   End Function
   
   Public Function ToDouble(provider As IFormatProvider) As Double _
                   Implements IConvertible.ToDouble
      If signBit = signBit.Negative Then
         Return Convert.ToDouble(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToDouble(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function   
   
   Public Function ToInt16(provider As IFormatProvider) As Int16 _
                   Implements IConvertible.ToInt16
      If signBit = signBit.Negative Then
         Return Convert.ToInt16(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt32(provider As IFormatProvider) As Int32 _
                   Implements IConvertible.ToInt32
      If signBit = signBit.Negative Then
         Return Convert.ToInt32(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToInt64(provider As IFormatProvider) As Int64 _
                   Implements IConvertible.ToInt64
      If signBit = signBit.Negative Then
         Return Convert.ToInt64(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToSByte(provider As IFormatProvider) As SByte _
                   Implements IConvertible.ToSByte
      If signBit = SignBit.Positive Then
         Try
            Return Convert.ToSByte(Byte.Parse(byteString, NumberStyles.HexNumber))
         Catch e As OverflowException
            Throw New OverflowException(String.Format("{0} is outside the range of the SByte type.", _
                                                   Byte.Parse(byteString, NumberStyles.HexNumber)), e)   
         End Try
      Else
         Return SByte.Parse(byteString, NumberStyles.HexNumber)
      End If
   End Function

   Public Function ToSingle(provider As IFormatProvider) As Single _
                   Implements IConvertible.ToSingle
      If signBit = signBit.Negative Then
         Return Convert.ToSingle(SByte.Parse(byteString, NumberStyles.HexNumber))
      Else
         Return Convert.ToSingle(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Overloads Function ToString(provider As IFormatProvider) As String _
                   Implements IConvertible.ToString
      Return Me.byteString
   End Function
   
   Public Function ToType(conversionType As Type, provider As IFormatProvider) As Object _
                   Implements IConvertible.ToType
      Select Case Type.GetTypeCode(conversionType)
         Case TypeCode.Boolean 
            Return Me.ToBoolean(Nothing)
         Case TypeCode.Byte
            Return Me.ToByte(Nothing)
         Case TypeCode.Char
            Return Me.ToChar(Nothing)
         Case TypeCode.DateTime
            Return Me.ToDateTime(Nothing)
         Case TypeCode.Decimal
            Return Me.ToDecimal(Nothing)
         Case TypeCode.Double
            Return Me.ToDouble(Nothing)
         Case TypeCode.Int16
            Return Me.ToInt16(Nothing)
         Case TypeCode.Int32
            Return Me.ToInt32(Nothing)
         Case TypeCode.Int64
            Return Me.ToInt64(Nothing)
         Case TypeCode.Object
            If GetType(ByteString).Equals(conversionType) Then
               Return Me
            Else
               Throw New InvalidCastException(String.Format("Conversion to a {0} is not supported.", conversionType.Name))
            End If 
         Case TypeCode.SByte
            Return Me.ToSByte(Nothing)
         Case TypeCode.Single
            Return Me.ToSingle(Nothing)
         Case TypeCode.String
            Return Me.ToString(Nothing)
         Case TypeCode.UInt16
            Return Me.ToUInt16(Nothing)
         Case TypeCode.UInt32
            Return Me.ToUInt32(Nothing)
         Case TypeCode.UInt64
            Return Me.ToUInt64(Nothing)   
         Case Else
            Throw New InvalidCastException(String.Format("Conversion to {0} is not supported.", conversionType.Name))   
            
      End Select
   End Function
   
   Public Function ToUInt16(provider As IFormatProvider) As UInt16 _
                   Implements IConvertible.ToUInt16
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt16 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt16(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function

   Public Function ToUInt32(provider As IFormatProvider) As UInt32 _
                   Implements IConvertible.ToUInt32
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt32 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt32(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
   Public Function ToUInt64(provider As IFormatProvider) As UInt64 _
                   Implements IConvertible.ToUInt64
      If signBit = signBit.Negative Then
         Throw New OverflowException(String.Format("{0} is outside the range of the UInt64 type.", _
                                                   SByte.Parse(byteString, NumberStyles.HexNumber)))
      Else
         Return Convert.ToUInt64(Byte.Parse(byteString, NumberStyles.HexNumber))
      End If   
   End Function
   
End Structure

下面的示例实例化几个 ByteString 对象,并调用 ToByte(Object, IFormatProvider) 方法将其转换为字节值。The following example instantiates several ByteString objects and calls the ToByte(Object, IFormatProvider) method to convert them to byte values. 它阐释了 ToByte(Object, IFormatProvider) 方法包装对 IConvertible.ToByte 要转换的对象的方法的调用。It illustrates that the ToByte(Object, IFormatProvider) method wraps a call to the IConvertible.ToByte method of the object to be converted.

public class Class1
{
   public static void Main()
   {
      byte positiveByte = 216;
      sbyte negativeByte = -101;

      ByteString positiveString = new ByteString();
      positiveString.Sign = (SignBit) Math.Sign(positiveByte);
      positiveString.Value = positiveByte.ToString("X2");

      ByteString negativeString = new ByteString();
      negativeString.Sign = (SignBit) Math.Sign(negativeByte);
      negativeString.Value = negativeByte.ToString("X2");

      try {
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToByte(positiveString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value);
      }

      try {
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToByte(negativeString));
      }
      catch (OverflowException) {
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value);
      }
   }
}
// The example displays the following output:
//       'D8' converts to 216.
//       0x9B is outside the range of the Byte type.
Module modMain
   Public Sub Main()
      Dim positiveByte As Byte = 216
      Dim negativeByte As SByte = -101
      
      
      Dim positiveString As New ByteString()
      positiveString.Sign = CType(Math.Sign(positiveByte), SignBit)
      positiveString.Value = positiveByte.ToString("X2")
      
      Dim negativeString As New ByteString()
      negativeString.Sign = CType(Math.Sign(negativeByte), SignBit)
      negativeString.Value = negativeByte.ToString("X2")
      
      Try
         Console.WriteLine("'{0}' converts to {1}.", positiveString.Value, Convert.ToByte(positiveString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", positiveString.Value)
      End Try

      Try
         Console.WriteLine("'{0}' converts to {1}.", negativeString.Value, Convert.ToByte(negativeString))
      Catch e As OverflowException
         Console.WriteLine("0x{0} is outside the range of the Byte type.", negativeString.Value)
      End Try   
   End Sub
End Module
' The example dosplays the following output:
'       'D8' converts to 216.
'       0x9B is outside the range of the Byte type.

注解

provider 使用户能够指定有关的内容的特定于区域性的转换信息 valueprovider enables the user to specify culture-specific conversion information about the contents of value. 基类型将忽略 provider ; 但是,如果 value 是实现接口的用户定义类型,则可以使用参数 IConvertibleThe base types ignore provider; however, the parameter may be used if value is a user-defined type that implements the IConvertible interface.

适用于

ToByte(String, IFormatProvider)

使用指定的区域性特定格式设置信息,将数字的指定字符串表示形式转换为等效的 8 位无符号整数。Converts the specified string representation of a number to an equivalent 8-bit unsigned integer, using specified culture-specific formatting information.

public:
 static System::Byte ToByte(System::String ^ value, IFormatProvider ^ provider);
public static byte ToByte (string value, IFormatProvider provider);
public static byte ToByte (string? value, IFormatProvider? provider);
static member ToByte : string * IFormatProvider -> byte
Public Shared Function ToByte (value As String, provider As IFormatProvider) As Byte

参数

value
String

包含要转换的数字的字符串。A string that contains the number to convert.

provider
IFormatProvider

一个提供区域性特定的格式设置信息的对象。An object that supplies culture-specific formatting information.

返回

Byte

一个与 value 等效的 8 位无符号整数,如果 valuenull,则为零。An 8-bit unsigned integer that is equivalent to value, or zero if value is null.

例外

value 不由一个可选符号后跟一系列数字 (0-9) 组成。value does not consist of an optional sign followed by a sequence of digits (0 through 9).

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例创建一个自定义 NumberFormatInfo 对象,该对象将正号定义为 "pos",将负号定义为 "neg",它将在对方法的调用中使用 ToByte(String, IFormatProvider)The following example creates a custom NumberFormatInfo object that defines the positive sign as "pos" and the negative sign as "neg", which it uses in calls to the ToByte(String, IFormatProvider) method. 然后,它将 ToByte(String, IFormatProvider) 重复调用方法,将字符串数组中的每个元素转换为一个 Byte 值。It then calls the ToByte(String, IFormatProvider) method repeatedly to convert each element in a string array to a Byte value.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      // Create a NumberFormatInfo object and set several of its
      // properties that apply to unsigned bytes.
      NumberFormatInfo provider = new NumberFormatInfo();

      // These properties affect the conversion.
      provider.PositiveSign = "pos ";
      provider.NegativeSign = "neg ";

      // This property does not affect the conversion.
      // The input string cannot have a decimal separator.
      provider.NumberDecimalSeparator = ".";

      // Define an array of numeric strings.
      string[] numericStrings = { "234", "+234", "pos 234", "234.", "255",
                                  "256", "-1" };

      foreach (string numericString in numericStrings)
      {
         Console.Write("'{0,-8}' ->   ", numericString);
         try {
            byte number = Convert.ToByte(numericString, provider);
            Console.WriteLine(number);
         }
         catch (FormatException) {
            Console.WriteLine("Incorrect Format");
         }
         catch (OverflowException) {
            Console.WriteLine("Overflows a Byte");
         }
      }
   }
}
// The example displays the following output:
//       '234     ' ->   234
//       '+234    ' ->   Incorrect Format
//       'pos 234 ' ->   234
//       '234.    ' ->   Incorrect Format
//       '255     ' ->   255
//       '256     ' ->   Overflows a Byte
//       '-1      ' ->   Incorrect Format
Imports System.Globalization

Module Example
   Public Sub Main()
      ' Create a NumberFormatInfo object and set several of its
      ' properties that apply to unsigned bytes.
      Dim provider As New NumberFormatInfo()
      With provider 
         ' These properties affect the conversion.
         .PositiveSign = "pos "
         .NegativeSign = "neg "

         ' This property does not affect the conversion.
         ' The input string cannot have a decimal separator.
         .NumberDecimalSeparator = "."
      End With
      
      ' Define an array of numeric strings.
      Dim numericStrings() As String = { "234", "+234", "pos 234", "234.", _
                                         "255", "256", "-1" }

      For Each numericString As String In numericStrings
         Console.Write("'{0,-8}' ->   ", numericString)
         Try
            Dim number As Byte = Convert.ToByte(numericString, provider)
            Console.WriteLine(number)
         Catch ex As FormatException
            Console.WriteLine("Incorrect Format")                          
         Catch ex As OverflowException
            Console.WriteLine("Overflows a Byte")
         End Try   
      Next
   End Sub   
End Module 
' The example displays the following output:
'       '234     ' ->   234
'       '+234    ' ->   Incorrect Format
'       'pos 234 ' ->   234
'       '234.    ' ->   Incorrect Format
'       '255     ' ->   255
'       '256     ' ->   Overflows a Byte
'       '-1      ' ->   Incorrect Format

注解

provider 是一个 IFormatProvider 获取对象的实例 NumberFormatInfoprovider is an IFormatProvider instance that obtains a NumberFormatInfo object. NumberFormatInfo对象提供有关的格式的区域性特定信息 valueThe NumberFormatInfo object provides culture-specific information about the format of value. 如果 providernull ,则 NumberFormatInfo 使用当前区域性的对象。If provider is null, the NumberFormatInfo object for the current culture is used.

如果你不希望在转换失败时处理异常,则可以改为调用 Byte.TryParse 方法。If you prefer not to handle an exception if the conversion fails, you can call the Byte.TryParse method instead. 它将返回一个 Boolean 值,该值指示转换是成功还是失败。It returns a Boolean value that indicates whether the conversion succeeded or failed.

另请参阅

适用于

ToByte(Single)

将指定的单精度浮点数的值转换为等效的 8 位无符号整数。Converts the value of the specified single-precision floating-point number to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(float value);
public static byte ToByte (float value);
static member ToByte : single -> byte
Public Shared Function ToByte (value As Single) As Byte

参数

value
Single

单精度浮点数。A single-precision floating-point number.

返回

Byte

value,舍入为最接近的 8 位无符号整数。value, rounded to the nearest 8-bit unsigned integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例将 Single 值转换为 ByteThe following example converts a Single value to a Byte.

public:
   void ConvertByteSingle( Byte byteVal )
   {
      float floatVal;
      
      // Byte to float conversion will not overflow.
      floatVal = System::Convert::ToSingle( byteVal );
      System::Console::WriteLine( "The Byte as a float is {0}.",
         floatVal );
      
      // Float to Byte conversion can overflow.
      try
      {
         byteVal = System::Convert::ToByte( floatVal );
         System::Console::WriteLine( "The float as a Byte is {0}.",
         byteVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine(
            "The float value is too large for a Byte." );
      }
   }
public void ConvertByteSingle(byte byteVal) {
    float floatVal;

    // Byte to float conversion will not overflow.
    floatVal = System.Convert.ToSingle(byteVal);
    System.Console.WriteLine("The byte as a float is {0}.",
        floatVal);

    // Float to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(floatVal);
        System.Console.WriteLine("The float as a byte is {0}.",
            byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "The float value is too large for a byte.");
    }
}
Public Sub ConvertByteSingle(ByVal byteVal As Byte)
    Dim singleVal As Single

    ' Byte to float conversion will not overflow.
    singleVal = System.Convert.ToSingle(byteVal)
    System.Console.WriteLine("The byte as a single is {0}.", _
                              singleVal)

    ' Single to byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(singleVal)
        System.Console.WriteLine("The single as a byte is {0}.", _
                                  byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in single-to-byte conversion.")
    End Try
End Sub

另请参阅

适用于

ToByte(UInt64)

重要

此 API 不符合 CLS。

将指定的 64 位无符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 64-bit unsigned integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::UInt64 value);
[System.CLSCompliant(false)]
public static byte ToByte (ulong value);
[<System.CLSCompliant(false)>]
static member ToByte : uint64 -> byte
Public Shared Function ToByte (value As ULong) As Byte

参数

value
UInt64

要转换的 64 位无符号整数。The 64-bit unsigned integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

属性

例外

value 大于 MaxValuevalue is greater than MaxValue.

示例

下面的示例将一个无符号长整数数组转换为 Byte 值。The following example converts an array of unsigned long integers to Byte values.

ulong[] numbers= { UInt64.MinValue, 121, 340, UInt64.MaxValue };
byte result;
foreach (ulong number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       Converted the UInt64 value 0 to the Byte value 0.
//       Converted the UInt64 value 121 to the Byte value 121.
//       The UInt64 value 340 is outside the range of the Byte type.
//       The UInt64 value 18446744073709551615 is outside the range of the Byte type.
Dim numbers() As ULong = { UInt64.MinValue, 121, 340, UInt64.MaxValue }
Dim result As Byte
For Each number As ULong In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       Converted the UInt64 value 0 to the Byte value 0.
'       Converted the UInt64 value 121 to the Byte value 121.
'       The UInt64 value 340 is outside the range of the Byte type.
'       The UInt64 value 18446744073709551615 is outside the range of the Byte type.

适用于

ToByte(SByte)

重要

此 API 不符合 CLS。

将指定的 8 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 8-bit signed integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::SByte value);
[System.CLSCompliant(false)]
public static byte ToByte (sbyte value);
[<System.CLSCompliant(false)>]
static member ToByte : sbyte -> byte
Public Shared Function ToByte (value As SByte) As Byte

参数

value
SByte

要转换的 8 位有符号整数。The 8-bit signed integer to be converted.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

属性

例外

value 小于 MinValuevalue is less than MinValue.

示例

下面的示例将值数组转换 SByteByte 值。The following example converts an array of SByte values to Byte values.

sbyte[] numbers = { SByte.MinValue, -1, 0, 10, SByte.MaxValue };
byte result;
foreach (sbyte number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The SByte value -128 is outside the range of the Byte type.
//       The SByte value -1 is outside the range of the Byte type.
//       Converted the SByte value 0 to the Byte value 0.
//       Converted the SByte value 10 to the Byte value 10.
//       Converted the SByte value 127 to the Byte value 127.
Dim numbers() As SByte = { SByte.MinValue, -1, 0, 10, SByte.MaxValue }
Dim result As Byte
For Each number As SByte In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The SByte value -128 is outside the range of the Byte type.
'       The SByte value -1 is outside the range of the Byte type.
'       Converted the SByte value 0 to the Byte value 0.
'       Converted the SByte value 10 to the Byte value 10.
'       Converted the SByte value 127 to the Byte value 127.

适用于

ToByte(Decimal)

将指定的十进制数的值转换为等效的 8 位无符号整数。Converts the value of the specified decimal number to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::Decimal value);
public static byte ToByte (decimal value);
static member ToByte : decimal -> byte
Public Shared Function ToByte (value As Decimal) As Byte

参数

value
Decimal

要转换的数字。The number to convert.

返回

Byte

value,舍入为最接近的 8 位无符号整数。value, rounded to the nearest 8-bit unsigned integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

注解

下面的示例将 Byte 值转换为 Decimal ,并将 Decimal 值转换为 ByteThe following example converts a Byte value to a Decimal and a Decimal value to a Byte.

public:
   void ConvertByteDecimal( Byte byteVal )
   {
      Decimal decimalVal;
      
      // Byte to decimal conversion will not overflow.
      decimalVal = System::Convert::ToDecimal( byteVal );
      System::Console::WriteLine( "The Byte as a decimal is {0}.",
         decimalVal );
      
      // Decimal to Byte conversion can overflow.
      try
      {
         byteVal = System::Convert::ToByte( decimalVal );
         System::Console::WriteLine( "The Decimal as a Byte is {0}.",
         byteVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine(
            "The decimal value is too large for a Byte." );
      }
   }
public void ConvertByteDecimal(byte byteVal) {
    decimal decimalVal;

    // Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal);
    System.Console.WriteLine("The byte as a decimal is {0}.",
        decimalVal);

    // Decimal to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(decimalVal);
        System.Console.WriteLine("The Decimal as a byte is {0}.",
            byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "The decimal value is too large for a byte.");
    }
}
Public Sub ConvertByteDecimal(ByVal byteVal As Byte)
    Dim decimalVal As Decimal

    ' Byte to decimal conversion will not overflow.
    decimalVal = System.Convert.ToDecimal(byteVal)
    System.Console.WriteLine("The byte as a decimal is {0}.", _
                              decimalVal)

    ' Decimal to byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(decimalVal)
        System.Console.WriteLine("The Decimal as a byte is {0}.", _
                                  byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in decimal-to-byte conversion.")
    End Try
End Sub

适用于

ToByte(Int64)

将指定的 64 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 64-bit signed integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(long value);
public static byte ToByte (long value);
static member ToByte : int64 -> byte
Public Shared Function ToByte (value As Long) As Byte

参数

value
Int64

要转换的 64 位带符号整数。The 64-bit signed integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

例外

value 小于 MinValue 或大于 MaxValuevalue is less than MinValue or greater than MaxValue.

示例

下面的示例将值数组转换 Int64Byte 值。The following example converts an array of Int64 values to Byte values.

long[] numbers = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue };
byte result;
foreach (long number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int64 value -9223372036854775808 is outside the range of the Byte type.
//       The Int64 value -1 is outside the range of the Byte type.
//       Converted the Int64 value 0 to the Byte value 0.
//       Converted the Int64 value 121 to the Byte value 121.
//       The Int64 value 340 is outside the range of the Byte type.
//       The Int64 value 9223372036854775807 is outside the range of the Byte type.
Dim numbers() As Long = { Int64.MinValue, -1, 0, 121, 340, Int64.MaxValue }
Dim result As Byte
For Each number As Long In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int64 value -9223372036854775808 is outside the range of the Byte type.
'       The Int64 value -1 is outside the range of the Byte type.
'       Converted the Int64 value 0 to the Byte value 0.
'       Converted the Int64 value 121 to the Byte value 121.
'       The Int64 value 340 is outside the range of the Byte type.
'       The Int64 value 9223372036854775807 is outside the range of the Byte type.      

适用于

ToByte(Byte)

返回指定的 8 位无符号整数;不执行任何实际的转换。Returns the specified 8-bit unsigned integer; no actual conversion is performed.

public:
 static System::Byte ToByte(System::Byte value);
public static byte ToByte (byte value);
static member ToByte : byte -> byte
Public Shared Function ToByte (value As Byte) As Byte

参数

value
Byte

要返回的 8 位无符号整数。The 8-bit unsigned integer to return.

返回

Byte

不经更改即返回 valuevalue is returned unchanged.

适用于

ToByte(Char)

将指定 Unicode 字符的值转换为等效的 8 位无符号整数。Converts the value of the specified Unicode character to the equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(char value);
public static byte ToByte (char value);
static member ToByte : char -> byte
Public Shared Function ToByte (value As Char) As Byte

参数

value
Char

要转换的 Unicode 字符。The Unicode character to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

例外

value 表示一个大于 MaxValue 的数字。value represents a number that is greater than MaxValue.

示例

下面的示例将值数组转换 CharByte 值。The following example converts an array of Char values to Byte values.

char[] chars = { 'a', 'z', '\x0007', '\x03FF' };
foreach (char ch in chars)
{
   try {
      byte result = Convert.ToByte(ch);
      Console.WriteLine("{0} is converted to {1}.", ch, result);
   }
   catch (OverflowException) {
      Console.WriteLine("Unable to convert u+{0} to a byte.",
                        Convert.ToInt16(ch).ToString("X4"));
   }
}
// The example displays the following output:
//       a is converted to 97.
//       z is converted to 122.
//        is converted to 7.
//       Unable to convert u+03FF to a byte.
Dim chars() As Char = { "a"c, "z"c, ChrW(7), ChrW(1023) }
For Each ch As Char in chars
   Try
      Dim result As Byte = Convert.ToByte(ch)
      Console.WriteLine("{0} is converted to {1}.", ch, result)
   Catch e As OverflowException
      Console.WriteLIne("Unable to convert u+{0} to a byte.", _
                        AscW(ch).ToString("X4"))
   End Try
Next   
' The example displays the following output:
'       a is converted to 97.
'       z is converted to 122.
'        is converted to 7.
'       Unable to convert u+03FF to a byte.      

注解

此方法返回一个无符号字节值,该值表示 Char 传递给它的对象的数值代码。This method returns an unsigned byte value that represents the numeric code of the Char object passed to it. 在 .NET 中, Char 对象为16位值。In .NET, a Char object is a 16-bit value. 这意味着,此方法适用于从 U + 0000 到 U + 00FF 返回 ASCII 字符范围或 Unicode C0 控件和基本拉丁语以及 C1 控件和拉丁语-1 补充范围中字符的数字代码。This means that the method is suitable for returning the numeric codes of characters in the ASCII character range or in the Unicode C0 Controls and Basic Latin, and C1 Controls and Latin-1 Supplement ranges, from U+0000 to U+00FF.

适用于

ToByte(DateTime)

调用此方法始终引发 InvalidCastExceptionCalling this method always throws InvalidCastException.

public:
 static System::Byte ToByte(DateTime value);
public static byte ToByte (DateTime value);
static member ToByte : DateTime -> byte
Public Shared Function ToByte (value As DateTime) As Byte

参数

value
DateTime

要转换的日期和时间值。The date and time value to convert.

返回

Byte

不支持此转换。This conversion is not supported. 不返回任何值。No value is returned.

例外

不支持此转换。This conversion is not supported.

适用于

ToByte(Boolean)

将指定的布尔值转换为等效的 8 位无符号整数。Converts the specified Boolean value to the equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(bool value);
public static byte ToByte (bool value);
static member ToByte : bool -> byte
Public Shared Function ToByte (value As Boolean) As Byte

参数

value
Boolean

要转换的布尔值。The Boolean value to convert.

返回

Byte

如果 valuetrue,则为数字 1;否则,为 0。The number 1 if value is true; otherwise, 0.

示例

下面的示例阐释了 Boolean 到值的转换 ByteThe following example illustrates the conversion of Boolean to Byte values.

using namespace System;

void main()
{
   bool falseFlag = false;
   bool trueFlag = true;

   Console::WriteLine("{0} converts to {1}.", falseFlag,
                      Convert::ToByte(falseFlag));
   Console::WriteLine("{0} converts to {1}.", trueFlag, 
                      Convert::ToByte(trueFlag));
}
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.
bool falseFlag = false;
bool trueFlag = true;

Console.WriteLine("{0} converts to {1}.", falseFlag,
                  Convert.ToByte(falseFlag));
Console.WriteLine("{0} converts to {1}.", trueFlag,
                  Convert.ToByte(trueFlag));
// The example displays the following output:
//       False converts to 0.
//       True converts to 1.
Dim falseFlag As Boolean = False
Dim trueFlag As Boolean = True

Console.WriteLine("{0} converts to {1}.", falseFlag, _
                  Convert.ToByte(falseFlag))
Console.WriteLine("{0} converts to {1}.", trueFlag, _
                  Convert.ToByte(trueFlag))
' The example displays the following output:
'       False converts to 0.
'       True converts to 1.

适用于

ToByte(Double)

将指定的双精度浮点数的值转换为等效的 8 位无符号整数。Converts the value of the specified double-precision floating-point number to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(double value);
public static byte ToByte (double value);
static member ToByte : double -> byte
Public Shared Function ToByte (value As Double) As Byte

参数

value
Double

要转换的双精度浮点数。The double-precision floating-point number to convert.

返回

Byte

value,舍入为最接近的 8 位无符号整数。value, rounded to the nearest 8-bit unsigned integer. 如果 value 为两个整数中间的数字,则返回二者中的偶数;即 4.5 转换为 4,而 5.5 转换为 6。If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6.

例外

value 大于 MaxValue 或小于 MinValuevalue is greater than MaxValue or less than MinValue.

示例

下面的示例将 Byte 值转换为 Double ,并将 Double 值转换为 ByteThe following example converts a Byte value to a Double and a Double value to a Byte.

public:
   void ConvertDoubleByte( double doubleVal )
   {
      Byte byteVal = 0;
      
      // Double to Byte conversion can overflow.
      try
      {
         byteVal = System::Convert::ToByte( doubleVal );
         System::Console::WriteLine( " {0} as a Byte is: {1}.",
         doubleVal, byteVal );
      }
      catch ( System::OverflowException^ ) 
      {
         System::Console::WriteLine( "Overflow in double-to-Byte conversion." );
      }
      
      // Byte to double conversion cannot overflow.
      doubleVal = System::Convert::ToDouble( byteVal );
      System::Console::WriteLine( " {0} as a double is: {1}.",
         byteVal, doubleVal );
   }
public void ConvertDoubleByte(double doubleVal) {
    byte	byteVal = 0;

    // Double to byte conversion can overflow.
    try {
        byteVal = System.Convert.ToByte(doubleVal);
        System.Console.WriteLine("{0} as a byte is: {1}.",
            doubleVal, byteVal);
    }
    catch (System.OverflowException) {
        System.Console.WriteLine(
            "Overflow in double-to-byte conversion.");
    }

    // Byte to double conversion cannot overflow.
    doubleVal = System.Convert.ToDouble(byteVal);
    System.Console.WriteLine("{0} as a double is: {1}.",
        byteVal, doubleVal);
}
Public Sub ConvertDoubleByte(ByVal doubleVal As Double)
    Dim byteVal As Byte = 0

    ' Double to Byte conversion can overflow.
    Try
        byteVal = System.Convert.ToByte(doubleVal)
        System.Console.WriteLine("{0} as a Byte is: {1}.", _
            doubleVal, byteVal)
    Catch exception As System.OverflowException
        System.Console.WriteLine( _
            "Overflow in Double-to-Byte conversion.")
    End Try

    ' Byte to Double conversion cannot overflow.
    doubleVal = System.Convert.ToDouble(byteVal)
    System.Console.WriteLine("{0} as a Double is: {1}.", _
                              byteVal, doubleVal)
End Sub

适用于

ToByte(Int16)

将指定的 16 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 16-bit signed integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(short value);
public static byte ToByte (short value);
static member ToByte : int16 -> byte
Public Shared Function ToByte (value As Short) As Byte

参数

value
Int16

要转换的 16 位带符号整数。The 16-bit signed integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

例外

value 小于 MinValue 或大于 MaxValuevalue is less than MinValue or greater than MaxValue.

示例

下面的示例将值数组转换 Int16Byte 值。The following example converts an array of Int16 values to Byte values.

short[] numbers = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue };
byte result;
foreach (short number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int16 value -32768 is outside the range of the Byte type.
//       The Int16 value -1 is outside the range of the Byte type.
//       Converted the Int16 value 0 to the Byte value 0.
//       Converted the Int16 value 121 to the Byte value 121.
//       The Int16 value 340 is outside the range of the Byte type.
//       The Int16 value 32767 is outside the range of the Byte type.
Dim numbers() As Short = { Int16.MinValue, -1, 0, 121, 340, Int16.MaxValue }
Dim result As Byte
For Each number As Short In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int16 value -32768 is outside the range of the Byte type.
'       The Int16 value -1 is outside the range of the Byte type.
'       Converted the Int16 value 0 to the Byte value 0.
'       Converted the Int16 value 121 to the Byte value 121.
'       The Int16 value 340 is outside the range of the Byte type.
'       The Int16 value 32767 is outside the range of the Byte type.

适用于

ToByte(Int32)

将指定的 32 位有符号整数的值转换为等效的 8 位无符号整数。Converts the value of the specified 32-bit signed integer to an equivalent 8-bit unsigned integer.

public:
 static System::Byte ToByte(int value);
public static byte ToByte (int value);
static member ToByte : int -> byte
Public Shared Function ToByte (value As Integer) As Byte

参数

value
Int32

要转换的 32 位带符号整数。The 32-bit signed integer to convert.

返回

Byte

一个与 value 等效的 8 位无符号整数。An 8-bit unsigned integer that is equivalent to value.

例外

value 小于 MinValue 或大于 MaxValuevalue is less than MinValue or greater than MaxValue.

示例

下面的示例将值数组转换 Int32Byte 值。The following example converts an array of Int32 values to Byte values.

int[] numbers = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue };
byte result;
foreach (int number in numbers)
{
   try {
      result = Convert.ToByte(number);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        number.GetType().Name, number,
                        result.GetType().Name, result);
   }
   catch (OverflowException) {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        number.GetType().Name, number);
   }
}
// The example displays the following output:
//       The Int32 value -2147483648 is outside the range of the Byte type.
//       The Int32 value -1 is outside the range of the Byte type.
//       Converted the Int32 value 0 to the Byte value 0.
//       Converted the Int32 value 121 to the Byte value 121.
//       The Int32 value 340 is outside the range of the Byte type.
//       The Int32 value 2147483647 is outside the range of the Byte type.
Dim numbers() As Integer = { Int32.MinValue, -1, 0, 121, 340, Int32.MaxValue }
Dim result As Byte
For Each number As Integer In numbers
   Try
      result = Convert.ToByte(number)
      Console.WriteLIne("Converted the {0} value {1} to the {2} value {3}.", _
                        number.GetType().Name, number, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        number.GetType().Name, number)
   End Try
Next
' The example displays the following output:
'       The Int32 value -2147483648 is outside the range of the Byte type.
'       The Int32 value -1 is outside the range of the Byte type.
'       Converted the Int32 value 0 to the Byte value 0.
'       Converted the Int32 value 121 to the Byte value 121.
'       The Int32 value 340 is outside the range of the Byte type.
'       The Int32 value 2147483647 is outside the range of the Byte type.      

适用于

ToByte(Object)

将指定对象的值转换为 8 位无符号整数。Converts the value of the specified object to an 8-bit unsigned integer.

public:
 static System::Byte ToByte(System::Object ^ value);
public static byte ToByte (object value);
public static byte ToByte (object? value);
static member ToByte : obj -> byte
Public Shared Function ToByte (value As Object) As Byte

参数

value
Object

用于实现 IConvertible 接口的对象,或为 nullAn object that implements the IConvertible interface, or null.

返回

Byte

一个与 value 等效的 8 位无符号整数,如果 valuenull,则为零。An 8-bit unsigned integer that is equivalent to value, or zero if value is null.

例外

value 未采用 Byte 值的属性格式。value is not in the property format for a Byte value.

value 不实现 IConvertiblevalue does not implement IConvertible.

-or-

不支持从 value 转换为 Byte 类型。Conversion from value to the Byte type is not supported.

value 表示一个小于 MinValue 或大于 MaxValue 的数字。value represents a number that is less than MinValue or greater than MaxValue.

示例

下面的示例使用 ToByte(Object) 方法将对象数组转换为 Byte 值。The following example uses the ToByte(Object) method to convert an array of objects to Byte values.

object[] values = { true, -12, 163, 935, 'x', "104", "103.0", "-1",
                    "1.00e2", "One", 1.00e2};
byte result;
foreach (object value in values)
{
   try {
      result = Convert.ToByte(value);
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.",
                        value.GetType().Name, value,
                        result.GetType().Name, result);
   }
   catch (OverflowException)
   {
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.",
                        value.GetType().Name, value);
   }
   catch (FormatException)
   {
      Console.WriteLine("The {0} value {1} is not in a recognizable format.",
                        value.GetType().Name, value);
   }
   catch (InvalidCastException)
   {
      Console.WriteLine("No conversion to a Byte exists for the {0} value {1}.",
                        value.GetType().Name, value);
   }
}
// The example displays the following output:
//       Converted the Boolean value True to the Byte value 1.
//       The Int32 value -12 is outside the range of the Byte type.
//       Converted the Int32 value 163 to the Byte value 163.
//       The Int32 value 935 is outside the range of the Byte type.
//       Converted the Char value x to the Byte value 120.
//       Converted the String value 104 to the Byte value 104.
//       The String value 103.0 is not in a recognizable format.
//       The String value -1 is outside the range of the Byte type.
//       The String value 1.00e2 is not in a recognizable format.
//       The String value One is not in a recognizable format.
//       Converted the Double value 100 to the Byte value 100.
Dim values() As Object = { True, -12, 163, 935, "x"c, "104", "103.0", "-1", _
                           "1.00e2", "One", 1.00e2}
Dim result As Byte
For Each value As Object In values
   Try
      result = Convert.ToByte(value)
      Console.WriteLine("Converted the {0} value {1} to the {2} value {3}.", _
                        value.GetType().Name, value, _
                        result.GetType().Name, result)
   Catch e As OverflowException
      Console.WriteLine("The {0} value {1} is outside the range of the Byte type.", _
                        value.GetType().Name, value)
   Catch e As FormatException
      Console.WriteLine("The {0} value {1} is not in a recognizable format.", _
                        value.GetType().Name, value)
   Catch e As InvalidCastException
      Console.WriteLine("No conversion to a Byte exists for the {0} value {1}.", _
                        value.GetType().Name, value)
                        
   End Try
Next                           
' The example displays the following output:
'       Converted the Boolean value True to the Byte value 1.
'       The Int32 value -12 is outside the range of the Byte type.
'       Converted the Int32 value 163 to the Byte value 163.
'       The Int32 value 935 is outside the range of the Byte type.
'       Converted the Char value x to the Byte value 120.
'       Converted the String value 104 to the Byte value 104.
'       The String value 103.0 is not in a recognizable format.
'       The String value -1 is outside the range of the Byte type.
'       The String value 1.00e2 is not in a recognizable format.
'       The String value One is not in a recognizable format.
'       Converted the Double value 100 to the Byte value 100.      

注解

如果不 valuenull ,则此方法包装对的 IConvertible.ToByte 基础类型的实现的调用 valueIf value is not null, this method wraps a call to the IConvertible.ToByte implementation of the underlying type of value.

适用于