Int32.TryParse Method

Definition

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the operation succeeded.

Overloads

TryParse(String, Int32)

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

TryParse(String, NumberStyles, IFormatProvider, Int32)

Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

TryParse(String, Int32)

Converts the string representation of a number to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

public static bool TryParse (string s, out int result);
Parameters
s
String

A string containing a number to convert.

result
Int32

When this method returns, contains the 32-bit signed integer value equivalent of the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not of the correct format, or represents a number less than MinValue or greater than MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Examples

The following example calls the Int32.TryParse(String, Int32) method with a number of different string values.

using namespace System;


   void TryToParse(String^ value)
   {
      Int32 number;
      bool result = Int32::TryParse(value, number);
      if (result) {
         Console::WriteLine("Converted '{0}' to {1}.", value, number);
      }
      else {
         if (value == nullptr) value = "";
         Console::WriteLine("Attempted conversion of '{0}' failed.", value);
      }
   }


void main()
{
      TryToParse(nullptr);
      TryToParse("160519");
      TryToParse("9432.0");
      TryToParse("16,667");
      TryToParse("   -322   ");
      TryToParse("+4302");
      TryToParse("(100);");
      TryToParse("01FA");
}
// The example displays the following output:
//      Attempted conversion of '' failed.
//      Converted '160519' to 160519.
//      Attempted conversion of '9432.0' failed.
//      Attempted conversion of '16,667' failed.
//      Converted '   -322   ' to -322.
//      Converted '+4302' to 4302.
//      Attempted conversion of '(100);' failed.
//      Attempted conversion of '01FA' failed.
using System;

public class Example
{
   public static void Main()
   {
      String[] values = { null, "160519", "9432.0", "16,667",
                          "   -322   ", "+4302", "(100);", "01FA" };
      foreach (var value in values) {
         int number;
   
         bool result = Int32.TryParse(value, out number);
         if (result)
         {
            Console.WriteLine("Converted '{0}' to {1}.", value, number);         
         }
         else
         {
//            if (value == null) value = ""; 
            Console.WriteLine("Attempted conversion of '{0}' failed.", 
                               value == null ? "<null>" : value);
         }
      }
   }
}
// The example displays the following output:
//       Attempted conversion of '<null>' failed.
//       Converted '160519' to 160519.
//       Attempted conversion of '9432.0' failed.
//       Attempted conversion of '16,667' failed.
//       Converted '   -322   ' to -322.
//       Converted '+4302' to 4302.
//       Attempted conversion of '(100);' failed.
//       Attempted conversion of '01FA' failed.
Module Example
   Public Sub Main()
      Dim values() As String = { Nothing, "160519", "9432.0", "16,667",
                                 "   -322   ", "+4302", "(100);", 
                                 "01FA" }

      For Each value In values
         Dim number As Integer
    
         Dim result As Boolean = Int32.TryParse(value, number)
         If result Then
            Console.WriteLine("Converted '{0}' to {1}.", value, number)
         Else
            Console.WriteLine("Attempted conversion of '{0}' failed.", 
                              If(value Is Nothing, "<null>", value))
         End If     
      Next
   End Sub
End Module
' The example displays the following output to the console:
'       Attempted conversion of '<null>' failed.
'       Converted '160519' to 160519.
'       Attempted conversion of '9432.0' failed.
'       Attempted conversion of '16,667' failed.
'       Converted '   -322   ' to -322.
'       Converted '+4302' to 4302.
'       Attempted conversion of '(100)' failed.
'       Attempted conversion of '01FA' failed.

Some of the strings that the TryParse(String, Int32) method is unable to convert in this example are:

  • "9432.0". The conversion fails because the string cannot contain a decimal separator; it must contain integral digits only.

  • "16,667". The conversion fails because the string cannot contain group separators; it must contain integral digits only.

  • "(100)". The conversion fails because the string cannot contain a negative sign other than the one defined by the current culture's NumberFormatInfo.NegativeSign and NumberFormatInfo.NumberNegativePattern properties.

  • "01FA". The conversion fails because the string cannot contain hexadecimal digits; it must contain decimal digits only.

Remarks

The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails. It eliminates the need to use exception handling to test for a FormatException in the event that s is invalid and cannot be successfully parsed.

The s parameter contains a number of the form:

[ws][sign]digits[ws]

Items in square brackets ([ and ]) are optional. The following table describes each element.

Element Description
ws Optional white space.
sign An optional sign.
digits A sequence of digits ranging from 0 to 9.

The s parameter is interpreted using the NumberStyles.Integer style. In addition to the decimal digits, only leading and trailing spaces together with a leading sign are allowed. To explicitly define the style elements together with the culture-specific formatting information that can be present in s, use the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) method.

The s parameter is parsed using the formatting information in a NumberFormatInfo object initialized for the current system culture. For more information, see CurrentInfo.

This overload of the TryParse method interprets all digits in the s parameter as decimal digits. To parse the string representation of a hexadecimal number, call the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) overload.

See Also

TryParse(String, NumberStyles, IFormatProvider, Int32)

Converts the string representation of a number in a specified style and culture-specific format to its 32-bit signed integer equivalent. A return value indicates whether the conversion succeeded.

public static bool TryParse (string s, System.Globalization.NumberStyles style, IFormatProvider provider, out int result);
Parameters
s
String

A string containing a number to convert. The string is interpreted using the style specified by style.

style
NumberStyles

A bitwise combination of enumeration values that indicates the style elements that can be present in s. A typical value to specify is Integer.

provider
IFormatProvider

An object that supplies culture-specific formatting information about s.

result
Int32

When this method returns, contains the 32-bit signed integer value equivalent of the number contained in s, if the conversion succeeded, or zero if the conversion failed. The conversion fails if the s parameter is null or Empty, is not in a format compliant with style, or represents a number less than MinValue or greater than MaxValue. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.

Returns

true if s was converted successfully; otherwise, false.

Exceptions

style is not a NumberStyles value.

-or-

style is not a combination of AllowHexSpecifier and HexNumber values.

Examples

The following example calls the Int32.TryParse(String, NumberStyles, IFormatProvider, Int32) method with a number of different string and NumberStyles values.

using namespace System;
using namespace System::Globalization;

void CallTryParse(String^ stringToConvert, NumberStyles styles)
{
      Int32 number;
      CultureInfo^ provider;

      // If currency symbol is allowed, use en-US culture. 
      if (((Int32) (styles & NumberStyles::AllowCurrencySymbol)) > 0)
         provider = gcnew CultureInfo("en-US");
      else
         provider = CultureInfo::InvariantCulture;

      bool result = Int32::TryParse(stringToConvert, styles, 
                                   provider, number);
      if (result)
         Console::WriteLine("Converted '{0}' to {1}.", stringToConvert, number);
      else
         Console::WriteLine("Attempted conversion of '{0}' failed.", 
                           Convert::ToString(stringToConvert));
}

void main()
{
      String^ numericString;
      NumberStyles styles;

      numericString = "106779";
      styles = NumberStyles::Integer;
      CallTryParse(numericString, styles);

      numericString = "-30677";
      styles = NumberStyles::None;
      CallTryParse(numericString, styles);

      styles = NumberStyles::AllowLeadingSign;
      CallTryParse(numericString, styles);

      numericString = "301677-";
      CallTryParse(numericString, styles);

      styles = styles | NumberStyles::AllowTrailingSign;
      CallTryParse(numericString, styles);

      numericString = "$10634";
      styles = NumberStyles::Integer;
      CallTryParse(numericString, styles);

      styles = NumberStyles::Integer | NumberStyles::AllowCurrencySymbol;
      CallTryParse(numericString, styles);

      numericString = "10345.00";
      styles = NumberStyles::Integer | NumberStyles::AllowDecimalPoint;
      CallTryParse(numericString, styles);

      numericString = "10345.72";
      styles = NumberStyles::Integer | NumberStyles::AllowDecimalPoint;
      CallTryParse(numericString, styles);

      numericString = "22,593"; 
      styles = NumberStyles::Integer | NumberStyles::AllowThousands;
      CallTryParse(numericString, styles);

      numericString = "12E-01";
      styles = NumberStyles::Integer | NumberStyles::AllowExponent;
      CallTryParse(numericString, styles); 

      numericString = "12E03";
      CallTryParse(numericString, styles); 

      numericString = "80c1";
      CallTryParse(numericString, NumberStyles::HexNumber);

      numericString = "0x80C1";
      CallTryParse(numericString, NumberStyles::HexNumber);      
      Console::ReadLine();
}
// The example displays the following output:
//      Converted '106779' to 106779.
//      Attempted conversion of '-30677' failed.
//      Converted '-30677' to -30677.
//      Attempted conversion of '301677-' failed.
//      Converted '301677-' to -301677.
//      Attempted conversion of '$10634' failed.
//      Converted '$10634' to 10634.
//      Converted '10345.00' to 10345.
//      Attempted conversion of '10345.72' failed.
//      Converted '22,593' to 22593.
//      Attempted conversion of '12E-01' failed.
//      Converted '12E03' to 12000.
//      Converted '80c1' to 32961.
//      Attempted conversion of '0x80C1' failed.
using System;
using System.Globalization;

public class StringParsing
{
   public static void Main()
   {
      string numericString;
      NumberStyles styles;
      
      numericString = "106779";
      styles = NumberStyles.Integer;
      CallTryParse(numericString, styles);

      numericString = "-30677";
      styles = NumberStyles.None;
      CallTryParse(numericString, styles);
      
      styles = NumberStyles.AllowLeadingSign;
      CallTryParse(numericString, styles);
      
      numericString = "301677-";
      CallTryParse(numericString, styles);
      
      styles = styles | NumberStyles.AllowTrailingSign;
      CallTryParse(numericString, styles);
      
      numericString = "$10634";
      styles = NumberStyles.Integer;
      CallTryParse(numericString, styles);
      
      styles = NumberStyles.Integer | NumberStyles.AllowCurrencySymbol;
      CallTryParse(numericString, styles);
      
      numericString = "10345.00";
      styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
      CallTryParse(numericString, styles);
      
      numericString = "10345.72";
      styles = NumberStyles.Integer | NumberStyles.AllowDecimalPoint;
      CallTryParse(numericString, styles);

      numericString = "22,593"; 
      styles = NumberStyles.Integer | NumberStyles.AllowThousands;
      CallTryParse(numericString, styles);
      
      numericString = "12E-01";
      styles = NumberStyles.Integer | NumberStyles.AllowExponent;
      CallTryParse(numericString, styles); 
          
      numericString = "12E03";
      CallTryParse(numericString, styles); 
      
      numericString = "80c1";
      CallTryParse(numericString, NumberStyles.HexNumber);
      
      numericString = "0x80C1";
      CallTryParse(numericString, NumberStyles.HexNumber);      
   }

   private static void CallTryParse(string stringToConvert, NumberStyles styles)
   {
      int number;
      CultureInfo provider;
      
      // If currency symbol is allowed, use en-US culture.
      if ((styles & NumberStyles.AllowCurrencySymbol) > 0)
         provider = new CultureInfo("en-US");
      else
         provider = CultureInfo.InvariantCulture;
            
      bool result = Int32.TryParse(stringToConvert, styles, 
                                   provider, out number);
      if (result)
         Console.WriteLine("Converted '{0}' to {1}.", stringToConvert, number);
      else
         Console.WriteLine("Attempted conversion of '{0}' failed.", 
                           Convert.ToString(stringToConvert));
   }
}
// The example displays the following output to the console:
//       Converted '106779' to 106779.
//       Attempted conversion of '-30677' failed.
//       Converted '-30677' to -30677.
//       Attempted conversion of '301677-' failed.
//       Converted '301677-' to -301677.
//       Attempted conversion of '$10634' failed.
//       Converted '$10634' to 10634.
//       Converted '10345.00' to 10345.
//       Attempted conversion of '10345.72' failed.
//       Converted '22,593' to 22593.
//       Attempted conversion of '12E-01' failed.
//       Converted '12E03' to 12000.
//       Converted '80c1' to 32961.
//       Attempted conversion of '0x80C1' failed.
Imports System.Globalization

Module StringParsing
   Public Sub Main()
      Dim numericString As String
      Dim styles As NumberStyles
      
      numericString = "106779"
      styles = NumberStyles.Integer
      CallTryParse(numericString, styles)
      
      numericString = "-30677"
      styles = NumberStyles.None
      CallTryParse(numericString, styles)
      
      styles = NumberStyles.AllowLeadingSign
      CallTryParse(numericString, styles)
      
      numericString = "301677-"
      CallTryParse(numericString, styles)
      
      styles = styles Or NumberStyles.AllowTrailingSign
      CallTryParse(numericString, styles)
      
      numericString = "$10634"
      styles = NumberStyles.Integer
      CallTryParse(numericString, styles)
      
      styles = NumberStyles.Integer Or NumberStyles.AllowCurrencySymbol
      CallTryParse(numericString, styles)

      numericString = "10345.00"
      styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
      CallTryParse(numericString, styles)
      
      numericString = "10345.72"
      styles = NumberStyles.Integer Or NumberStyles.AllowDecimalPoint
      CallTryParse(numericString, styles)

      numericString = "22,593" 
      styles = NumberStyles.Integer Or NumberStyles.AllowThousands
      CallTryParse(numericString, styles)
      
      numericString = "12E-01"
      styles = NumberStyles.Integer Or NumberStyles.AllowExponent
      CallTryParse(numericString, styles) 
          
      numericString = "12E03"
      CallTryParse(numericString, styles) 
      
      numericString = "80c1"
      CallTryParse(numericString, NumberStyles.HexNumber)
      
      numericString = "0x80C1"
      CallTryParse(numericString, NumberStyles.HexNumber)
   End Sub
   
   Private Sub CallTryParse(stringToConvert As String, styles AS NumberStyles)
      Dim number As Integer
      Dim provider As CultureInfo
      
      ' If currency symbol is allowed, use en-US culture.
      If CBool(styles And NumberStyles.AllowCurrencySymbol) Then
         provider = CultureInfo.CurrentCulture
      Else
         provider = New CultureInfo("en-US")
      End If
      
      Dim result As Boolean = Int32.TryParse(stringToConvert, styles, _
                                             provider, number)
      If result Then
         Console.WriteLine("Converted '{0}' to {1}.", stringToConvert, number)
      Else
         Console.WriteLine("Attempted conversion of '{0}' failed.", _
                           Convert.ToString(stringToConvert))
      End If                                                                           
   End Sub
End Module
' The example displays the following output to the console:
'       Converted '106779' to 106779.
'       Attempted conversion of '-30677' failed.
'       Converted '-30677' to -30677.
'       Attempted conversion of '301677-' failed.
'       Converted '301677-' to -301677.
'       Attempted conversion of '$10634' failed.
'       Converted '$10634' to 10634.
'       Converted '10345.00' to 10345.
'       Attempted conversion of '10345.72' failed.
'       Converted '22,593' to 22593.
'       Attempted conversion of '12E-01' failed.
'       Converted '12E03' to 12000.
'       Converted '80c1' to 32961.
'       Attempted conversion of '0x80C1' failed.

Remarks

The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails. It eliminates the need to use exception handling to test for a FormatException in the event that s is invalid and cannot be parsed successfully.

The style parameter defines the style elements (such as white space or a positive or negative sign) that are allowed in the s parameter for the parse operation to succeed. It must be a combination of bit flags from the NumberStyles enumeration. Depending on the value of style, the s parameter may include the following elements:

[ws][$][sign][digits,]digits[.fractional_digits][e[sign]digits][ws]

Or, if the style parameter includes AllowHexSpecifier:

[ws]hexdigits[ws]

Items in square brackets ([ and ]) are optional. The following table describes each element.

Element Description
ws Optional white space. White space can appear at the beginning of s if style includes the NumberStyles.AllowLeadingWhite flag, or at the end of s if style includes the NumberStyles.AllowTrailingWhite flag.
$ A culture-specific currency symbol. Its position in the string is defined by the CurrencyPositivePattern property of the NumberFormatInfo object returned by the GetFormat method of the provider parameter. The currency symbol can appear in s if style includes the NumberStyles.AllowCurrencySymbol flag.
sign An optional sign. A sign symbol can appear in s if style includes the NumberStyles.AllowLeadingSign or NumberStyles.AllowTrailingSign flags.
digits A sequence of digits from 0 through 9.
, A culture-specific thousands separator. The thousands separator of the culture specified by provider can appear in s if style includes the NumberStyles.AllowThousands flag.
. A culture-specific decimal point symbol. The decimal point symbol of the culture specified by provider can appear in s if style includes the NumberStyles.AllowDecimalPoint flag.
fractional_digits One or more occurrences of the digit 0. Fractional digits can appear in s only if style includes the NumberStyles.AllowDecimalPoint flag.
e The 'e' or 'E' character, which indicates that the value is represented in exponential notation. The s parameter can represent a number in exponential notation if style includes the NumberStyles.AllowExponent flag.
hexdigits A sequence of hexadecimal digits from 0 through f, or 0 through F.

A string with decimal digits only (which corresponds to the NumberStyles.None flag) always parses successfully. Most of the remaining NumberStyles members control elements that may be but are not required to be present in this input string. The following table indicates how individual NumberStyles members affect the elements that may be present in s.

Non-composite NumberStyles values Elements permitted in s in addition to digits
NumberStyles.None Decimal digits only.
NumberStyles.AllowDecimalPoint The decimal point (.) and fractional_digits elements. However, fractional_digits must consist of only one or more 0 digits or the method returns false.
NumberStyles.AllowExponent The s parameter can also use exponential notation. If s represents a number in exponential notation, it must represent an integer within the range of the Int32 data type without a non-zero, fractional component.
NumberStyles.AllowLeadingWhite The ws element at the beginning of s.
NumberStyles.AllowTrailingWhite The ws element at the end of s.
NumberStyles.AllowLeadingSign A sign can appear before digits.
NumberStyles.AllowTrailingSign A sign can appear after digits.
NumberStyles.AllowParentheses The sign element in the form of parentheses enclosing the numeric value.
NumberStyles.AllowThousands The thousands separator (,) element.
NumberStyles.AllowCurrencySymbol The $ element.
NumberStyles.Currency All elements. The s parameter cannot represent a hexadecimal number or a number in exponential notation.
NumberStyles.Float The ws element at the beginning or end of s, sign at the beginning of s, and the decimal point (.) symbol. The s parameter can also use exponential notation.
NumberStyles.Number The ws, sign, thousands separator (,), and decimal point (.) elements.
NumberStyles.Any All styles, except s cannot represent a hexadecimal number.

If the NumberStyles.AllowHexSpecifier flag is used, s must be a hexadecimal value without a prefix. For example, "C9AF3" parses successfully, but "0xC9AF3" does not. The only other flags that can be present in style are NumberStyles.AllowLeadingWhite and NumberStyles.AllowTrailingWhite. (The NumberStyles enumeration has a composite style, NumberStyles.HexNumber, that includes both white space flags.)

The provider parameter is an IFormatProvider implementation, such as a CultureInfo object or a NumberFormatInfo object, whose GetFormat method returns a NumberFormatInfo object. The NumberFormatInfo object provides culture-specific information about the format of s. If provider is null, the NumberFormatInfo object for the current culture is used.

See Also

Applies to