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Boolean.Parse Method

Updated: September 2010

Converts the specified string representation of a logical value to its Boolean equivalent, or throws an exception if the string is not equivalent to the value of Boolean.TrueString or Boolean.FalseString.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static bool Parse(
	string value
)

Parameters

value
Type: System.String

A string containing the value to convert.

Return Value

Type: System.Boolean
true if value is equivalent to the value of the Boolean.TrueString field; false if value is equivalent to the value of the Boolean.FalseString field.

ExceptionCondition
ArgumentNullException

value is null.

FormatException

value is not equivalent to the value of the TrueString or FalseString field.

The value parameter, optionally preceded or trailed by white space, must contain a string that is equivalent to the value of either the Boolean.TrueString or Boolean.FalseString field; otherwise, a FormatException is thrown. The comparison is case-insensitive.

The following example calls the Parse method to parse an array of strings. Note that the parse operation succeeds only if the string to be parsed is "True" (the value of the TrueString field) or "False" (the value of the FalseString field) in a case-insensitive comparison.

using System;

public class Example
{
   public static void Main()
   {
      string[] values = { null, String.Empty, "True", "False", 
                          "true", "false", "    true    ", "0", 
                          "1", "-1", "string" };
      foreach (var value in values) {
         try {
            bool flag = Boolean.Parse(value);
            Console.WriteLine("'{0}' --> {1}", value, flag);
         }
         catch (ArgumentException) {
            Console.WriteLine("Cannot parse a null string.");
         }   
         catch (FormatException) {
            Console.WriteLine("Cannot parse '{0}'.", value);
         }         
      }                                     
   }
}
// The example displays the following output: 
//       Cannot parse a null string. 
//       Cannot parse ''. 
//       'True' --> True 
//       'False' --> False 
//       'true' --> True 
//       'false' --> False 
//       '    true    ' --> True 
//       Cannot parse '0'. 
//       Cannot parse '1'. 
//       Cannot parse '-1'. 
//       Cannot parse 'string'.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

September 2010

Revised extensively and replaced the example.

Customer feedback.

June 2010

Corrected return value information.

Customer feedback.

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