Boolean.Parse Method

May 11, 2014

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 TrueString field; false if value is equivalent to the value of the 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 TrueString or 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 Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      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);
            outputBlock.Text += String.Format("'{0}' --> {1}", value, flag) + "\n";
         }
         catch (ArgumentException)
         {
            outputBlock.Text += "Cannot parse a null string." + "\n";
         }
         catch (FormatException)
         {
            outputBlock.Text += String.Format("Cannot parse '{0}'.", value) + "\n";
         }
      }
   }
}
// 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 Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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