Parse Method

Boolean.Parse Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

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)

'Declaration
Public Shared Function Parse ( _
	value As String _
) As Boolean

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 Nothing.

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.


Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim values() As String = { Nothing, String.Empty, "True", "False", 
                                 "true", "false", "    true    ", "0", 
                                 "1", "-1", "string" }
      For Each value In values
         Try
            Dim flag As Boolean = Boolean.Parse(value)
            outputBlock.Text += String.Format("'{0}' --> {1}", value, flag) & vbCrLf
         Catch e As ArgumentException
            outputBlock.Text &= "Cannot parse a null string." & vbCrLf
         Catch e As FormatException
            outputBlock.Text += String.Format("Cannot parse '{0}'.", value) & vbCrLf
         End Try
      Next
   End Sub
End Module
' 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

Show:
© 2017 Microsoft