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.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.String
A string containing the value to convert.
Return Value
Type: System.Booleantrue if value is equivalent to the value of the TrueString field; false if value is equivalent to the value of the FalseString field.
| Exception | Condition |
|---|---|
| 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'.