Enum.Parse 方法

定义

将一个或多个枚举常数的名称或数字值的字符串表示转换成等效的枚举对象。Converts the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object.

重载

Parse(Type, String)

将一个或多个枚举常数的名称或数字值的字符串表示转换成等效的枚举对象。Converts the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object.

Parse(Type, String, Boolean)

将一个或多个枚举常数的名称或数字值的字符串表示转换成等效的枚举对象。Converts the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object. 一个参数指定该操作是否不区分大小写。A parameter specifies whether the operation is case-insensitive.

Parse<TEnum>(String, Boolean)
Parse<TEnum>(String)

Parse(Type, String)

将一个或多个枚举常数的名称或数字值的字符串表示转换成等效的枚举对象。Converts the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object.

public:
 static System::Object ^ Parse(Type ^ enumType, System::String ^ value);
[System.Runtime.InteropServices.ComVisible(true)]
public static object Parse (Type enumType, string value);
static member Parse : Type * string -> obj
Public Shared Function Parse (enumType As Type, value As String) As Object

参数

enumType
Type

枚举类型。An enumeration type.

value
String

包含要转换的值或名称的字符串。A string containing the name or value to convert.

返回

enumType 类型的对象,其值由 value 表示。An object of type enumType whose value is represented by value.

属性

异常

enumTypevaluenullenumType or value is null.

enumType 不是 EnumenumType is not an Enum.

-or- value 为空字符串或只包含空格。value is either an empty string or only contains white space.

-or- value 是一个名称,而不是为该枚举定义的命名常量之一。value is a name, but not one of the named constants defined for the enumeration.

value 超出了 enumType 的基础类型范围。value is outside the range of the underlying type of enumType.

示例

下面的示例使用 Parse(Type, String) 方法来分析通过调用 GetNames 方法创建的字符串数组。The following example uses the Parse(Type, String) method to parse an array of strings that are created by calling the GetNames method. 它还使用 Parse(Type, String) 方法来分析由位域组成的枚举值。It also uses the Parse(Type, String) method to parse an enumeration value that consists of a bit field.

using namespace System;

[Flags]
enum class Colors
{
   Red = 1,
   Green = 2,
   Blue = 4,
   Yellow = 8
};

int main()
{
   Console::WriteLine(  "The entries of the Colors enumeration are:" );
   Array^ a = Enum::GetNames( Colors::typeid );
   Int32 i = 0;
   while ( i < a->Length )
   {
      Object^ o = a->GetValue( i );
      Console::WriteLine( o->ToString() );
      i++;
   }

   Console::WriteLine();
   Object^ orange = Enum::Parse( Colors::typeid,  "Red, Yellow" );
   Console::WriteLine("The orange value has the combined entries of {0}", orange );
}

/*
This code example produces the following results:

The entries of the Colors Enum are:
Red
Green
Blue
Yellow

The orange value has the combined entries of Red, Yellow

*/
using System;

public class ParseTest
{
    [Flags]
    enum Colors { Red = 1, Green = 2, Blue = 4, Yellow = 8 };

    public static void Main()
    {
        Console.WriteLine("The entries of the Colors enumeration are:");
        foreach (string colorName in Enum.GetNames(typeof(Colors)))
        {
            Console.WriteLine("{0} = {1:D}", colorName, 
                                         Enum.Parse(typeof(Colors), colorName));
        }
        Console.WriteLine();

        Colors orange = (Colors) Enum.Parse(typeof(Colors), "Red, Yellow");
        Console.WriteLine("The orange value {0:D} has the combined entries of {0}", 
                           orange);
    }
}

/*
This code example produces the following results:

The entries of the Colors Enum are:
Red = 1
Green = 2
Blue = 4
Yellow = 8

The orange value 9 has the combined entries of Red, Yellow

*/
Public Class ParseTest

    <Flags()> _
    Enum Colors
        Red = 1
        Green = 2
        Blue = 4
        Yellow = 8
    End Enum

    Public Shared Sub Main()
        Console.WriteLine("The entries of the Colors enumeration are:")
        Dim colorName As String
        For Each colorName In [Enum].GetNames(GetType(Colors))
            Console.WriteLine("{0} = {1:D}", colorName, [Enum].Parse(GetType(Colors), colorName))
        Next
        Console.WriteLine()

        Dim orange As Colors = CType([Enum].Parse(GetType(Colors), "Red, Yellow"), Colors)
        Console.WriteLine("The orange value {0:D} has the combined entries of {0}", orange)
    End Sub
End Class

'This example displays the following output:
'
'The entries of the Colors Enum are:
'Red = 1
'Green = 2
'Blue = 4
'Yellow = 8
'
'The myOrange value 9 has the combined entries of Red, Yellow
'

注解

value 参数包含枚举成员的基础值或命名常量的字符串表示形式,或者包含用逗号(,)分隔的命名常量的列表。The value parameter contains the string representation of an enumeration member's underlying value or named constant, or a list of named constants delimited by commas (,). value中,一个或多个空格可以位于每个值、名称或逗号的前面或后面。One or more blank spaces can precede or follow each value, name, or comma in value. 如果 value 是列表,则返回值是与按位 OR 运算组合在一起的指定名称的值。If value is a list, the return value is the value of the specified names combined with a bitwise OR operation.

如果 value 是不对应于 enumType的命名常数的名称,则该方法将引发一个 ArgumentExceptionIf value is a name that does not correspond to a named constant of enumType, the method throws an ArgumentException. 如果 value 是整数的字符串表示形式,而该整数不表示 enumType 枚举的基础值,则该方法将返回其基础值 value 转换为整型的枚举成员。If value is the string representation of an integer that does not represent an underlying value of the enumType enumeration, the method returns an enumeration member whose underlying value is value converted to an integral type. 如果不需要此行为,请调用 IsDefined 方法,以确保整数的特定字符串表示形式确实是 enumType的成员。If this behavior is undesirable, call the IsDefined method to ensure that a particular string representation of an integer is actually a member of enumType. 下面的示例定义了一个 Colors 枚举,调用 Parse(Type, String) 方法将字符串转换为其对应的枚举值,并调用 IsDefined 方法以确保特定整数值是中的基础值 Colors枚举.The following example defines a Colors enumeration, calls the Parse(Type, String) method to convert strings to their corresponding enumeration values, and calls the IsDefined method to ensure that particular integral values are underlying values in the Colors enumeration.

using System;

[Flags] enum Colors { None=0, Red = 1, Green = 2, Blue = 4 };
   
public class Example
{
   public static void Main()
   {
      string[] colorStrings = { "0", "2", "8", "blue", "Blue", "Yellow", "Red, Green" };
      foreach (string colorString in colorStrings)
      {
         try {
            Colors colorValue = (Colors) Enum.Parse(typeof(Colors), colorString);        
            if (Enum.IsDefined(typeof(Colors), colorValue) | colorValue.ToString().Contains(","))  
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString());
            else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString);
         }
         catch (ArgumentException) {
            Console.WriteLine("'{0}' is not a member of the Colors enumeration.", colorString);
         }
      }
   }
}
// The example displays the following output:
//       Converted '0' to None.
//       Converted '2' to Green.
//       8 is not an underlying value of the Colors enumeration.
//       'blue' is not a member of the Colors enumeration.
//       Converted 'Blue' to Blue.
//       'Yellow' is not a member of the Colors enumeration.
//       Converted 'Red, Green' to Red, Green.
<Flags> Enum Colors As Integer
   None = 0
   Red = 1
   Green = 2
   Blue = 4
End Enum

Module Example
   Public Sub Main()
      Dim colorStrings() As String = {"0", "2", "8", "blue", "Blue", "Yellow", "Red, Green"}
      For Each colorString As String In colorStrings
         Try
            Dim colorValue As Colors = CType([Enum].Parse(GetType(Colors), colorString), Colors)        
            If [Enum].IsDefined(GetType(Colors), colorValue) Or colorValue.ToString().Contains(",") Then 
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString())
            Else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString)            
            End If                    
         Catch e As ArgumentException
            Console.WriteLine("'{0}' is not a member of the Colors enumeration.", colorString)
         End Try
      Next
   End Sub
End Module
' The example displays the following output:
'       Converted '0' to None.
'       Converted '2' to Green.
'       8 is not an underlying value of the Colors enumeration.
'       'blue' is not a member of the Colors enumeration.
'       Converted 'Blue' to Blue.
'       'Yellow' is not a member of the Colors enumeration.
'       Converted 'Red, Green' to Red, Green.

此操作区分大小写。This operation is case-sensitive.

另请参阅

Parse(Type, String, Boolean)

将一个或多个枚举常数的名称或数字值的字符串表示转换成等效的枚举对象。Converts the string representation of the name or numeric value of one or more enumerated constants to an equivalent enumerated object. 一个参数指定该操作是否不区分大小写。A parameter specifies whether the operation is case-insensitive.

public:
 static System::Object ^ Parse(Type ^ enumType, System::String ^ value, bool ignoreCase);
[System.Runtime.InteropServices.ComVisible(true)]
public static object Parse (Type enumType, string value, bool ignoreCase);
static member Parse : Type * string * bool -> obj
Public Shared Function Parse (enumType As Type, value As String, ignoreCase As Boolean) As Object

参数

enumType
Type

枚举类型。An enumeration type.

value
String

包含要转换的值或名称的字符串。A string containing the name or value to convert.

ignoreCase
Boolean

true 为忽略大小写;false 为考虑大小写。true to ignore case; false to regard case.

返回

enumType 类型的对象,其值由 value 表示。An object of type enumType whose value is represented by value.

属性

异常

enumTypevaluenullenumType or value is null.

enumType 不是 EnumenumType is not an Enum.

-or- value 为空字符串 ("") 或只包含空格。value is either an empty string ("") or only contains white space.

-or- value 是一个名称,而不是为该枚举定义的命名常量之一。value is a name, but not one of the named constants defined for the enumeration.

value 超出了 enumType 的基础类型范围。value is outside the range of the underlying type of enumType.

示例

下面的示例使用 Parse(Type, String, Boolean) 方法来分析通过调用 GetNames 方法创建的字符串数组。The following example uses the Parse(Type, String, Boolean) method to parse an array of strings that are created by calling the GetNames method. 它还使用 Parse(Type, String) 方法来分析由位域组成的枚举值。It also uses the Parse(Type, String) method to parse an enumeration value that consists of a bit field.

using System;

[Flags] enum Colors { None=0, Red = 1, Green = 2, Blue = 4 };
   
public class Example
{
   public static void Main()
   {
      string[] colorStrings = { "0", "2", "8", "blue", "Blue", "Yellow", "Red, Green" };
      foreach (string colorString in colorStrings)
      {
         try {
            Colors colorValue = (Colors) Enum.Parse(typeof(Colors), colorString, true);        
            if (Enum.IsDefined(typeof(Colors), colorValue) | colorValue.ToString().Contains(","))  
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString());
            else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString);
         }
         catch (ArgumentException) {
            Console.WriteLine("{0} is not a member of the Colors enumeration.", colorString);
         }
      }
   }
}
// The example displays the following output:
//       Converted '0' to None.
//       Converted '2' to Green.
//       8 is not an underlying value of the Colors enumeration.
//       Converted 'blue' to Blue.
//       Converted 'Blue' to Blue.
//       Yellow is not a member of the Colors enumeration.
//       Converted 'Red, Green' to Red, Green.
<Flags> Enum Colors As Integer
   None = 0
   Red = 1
   Green = 2
   Blue = 4
End Enum

Module Example
   Public Sub Main()
      Dim colorStrings() As String = {"0", "2", "8", "blue", "Blue", "Yellow", "Red, Green"}
      For Each colorString As String In colorStrings
         Try
            Dim colorValue As Colors = CType([Enum].Parse(GetType(Colors), colorString, True), Colors)        
            If [Enum].IsDefined(GetType(Colors), colorValue) Or colorValue.ToString().Contains(",") Then 
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString())
            Else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString)            
            End If                    
         Catch e As ArgumentException
            Console.WriteLine("{0} is not a member of the Colors enumeration.", colorString)
         End Try
      Next
   End Sub
End Module
' The example displays the following output:
'       Converted '0' to None.
'       Converted '2' to Green.
'       8 is not an underlying value of the Colors enumeration.
'       Converted 'blue' to Blue.
'       Converted 'Blue' to Blue.
'       Yellow is not a member of the Colors enumeration.
'       Converted 'Red, Green' to Red, Green.

注解

value 参数包含枚举成员的基础值或命名常量的字符串表示形式,或者包含用逗号(,)分隔的命名常量的列表。The value parameter contains the string representation of an enumeration member's underlying value or named constant, or a list of named constants delimited by commas (,). value中,一个或多个空格可以位于每个值、名称或逗号的前面或后面。One or more blank spaces can precede or follow each value, name, or comma in value. 如果 value 是列表,则返回值是与按位 OR 运算组合在一起的指定名称的值。If value is a list, the return value is the value of the specified names combined with a bitwise OR operation.

如果 value 是不对应于 enumType的命名常数的名称,则该方法将引发一个 ArgumentExceptionIf value is a name that does not correspond to a named constant of enumType, the method throws an ArgumentException. 如果 value 是整数的字符串表示形式,而该整数不表示 enumType 枚举的基础值,则该方法将返回其基础值 value 转换为整型的枚举成员。If value is the string representation of an integer that does not represent an underlying value of the enumType enumeration, the method returns an enumeration member whose underlying value is value converted to an integral type. 如果不需要此行为,请调用 IsDefined 方法,以确保整数的特定字符串表示形式确实是 enumType的成员。If this behavior is undesirable, call the IsDefined method to ensure that a particular string representation of an integer is actually a member of enumType. 下面的示例定义了一个 Colors 枚举,调用 Parse(Type, String, Boolean) 方法将字符串转换为其对应的枚举值,并调用 IsDefined 方法以确保特定整数值是中的基础值 Colors枚举.The following example defines a Colors enumeration, calls the Parse(Type, String, Boolean) method to convert strings to their corresponding enumeration values, and calls the IsDefined method to ensure that particular integral values are underlying values in the Colors enumeration.

using System;

[Flags] enum Colors { None=0, Red = 1, Green = 2, Blue = 4 };
   
public class Example
{
   public static void Main()
   {
      string[] colorStrings = { "0", "2", "8", "blue", "Blue", "Yellow", "Red, Green" };
      foreach (string colorString in colorStrings)
      {
         try {
            Colors colorValue = (Colors) Enum.Parse(typeof(Colors), colorString, true);        
            if (Enum.IsDefined(typeof(Colors), colorValue) | colorValue.ToString().Contains(","))  
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString());
            else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString);
         }
         catch (ArgumentException) {
            Console.WriteLine("{0} is not a member of the Colors enumeration.", colorString);
         }
      }
   }
}
// The example displays the following output:
//       Converted '0' to None.
//       Converted '2' to Green.
//       8 is not an underlying value of the Colors enumeration.
//       Converted 'blue' to Blue.
//       Converted 'Blue' to Blue.
//       Yellow is not a member of the Colors enumeration.
//       Converted 'Red, Green' to Red, Green.
<Flags> Enum Colors As Integer
   None = 0
   Red = 1
   Green = 2
   Blue = 4
End Enum

Module Example
   Public Sub Main()
      Dim colorStrings() As String = {"0", "2", "8", "blue", "Blue", "Yellow", "Red, Green"}
      For Each colorString As String In colorStrings
         Try
            Dim colorValue As Colors = CType([Enum].Parse(GetType(Colors), colorString, True), Colors)        
            If [Enum].IsDefined(GetType(Colors), colorValue) Or colorValue.ToString().Contains(",") Then 
               Console.WriteLine("Converted '{0}' to {1}.", colorString, colorValue.ToString())
            Else
               Console.WriteLine("{0} is not an underlying value of the Colors enumeration.", colorString)            
            End If                    
         Catch e As ArgumentException
            Console.WriteLine("{0} is not a member of the Colors enumeration.", colorString)
         End Try
      Next
   End Sub
End Module
' The example displays the following output:
'       Converted '0' to None.
'       Converted '2' to Green.
'       8 is not an underlying value of the Colors enumeration.
'       Converted 'blue' to Blue.
'       Converted 'Blue' to Blue.
'       Yellow is not a member of the Colors enumeration.
'       Converted 'Red, Green' to Red, Green.

ignoreCase 参数指定此操作是否区分大小写。The ignoreCase parameter specifies whether this operation is case-sensitive.

另请参阅

Parse<TEnum>(String, Boolean)

public:
generic <typename TEnum>
 where TEnum : value class static TEnum Parse(System::String ^ value, bool ignoreCase);
public static TEnum Parse<TEnum> (string value, bool ignoreCase) where TEnum : struct;
static member Parse : string * bool -> 'Enum (requires 'Enum : struct)
Public Shared Function Parse(Of TEnum As Structure) (value As String, ignoreCase As Boolean) As TEnum

类型参数

TEnum

参数

value
String
ignoreCase
Boolean

返回

TEnum

Parse<TEnum>(String)

public:
generic <typename TEnum>
 where TEnum : value class static TEnum Parse(System::String ^ value);
public static TEnum Parse<TEnum> (string value) where TEnum : struct;
static member Parse : string -> 'Enum (requires 'Enum : struct)
Public Shared Function Parse(Of TEnum As Structure) (value As String) As TEnum

类型参数

TEnum

参数

value
String

返回

TEnum

适用于