Updated: September 2010
Tries to convert the specified string representation of a logical value to its Boolean equivalent. A return value indicates whether the conversion succeeded or failed.
Assembly: mscorlib (in mscorlib.dll)
Public Shared Function TryParse ( _
value As String, _
<OutAttribute> ByRef result As Boolean _
) As Booleanpublic static bool TryParse(
string value,
out bool result
)public:
static bool TryParse(
String^ value,
[OutAttribute] bool% result
)static member TryParse :
value:string *
result:bool byref -> bool
Parameters
- value
- Type: System
. . :: . String
A string containing the value to convert.
- result
- Type: System
. . :: . Boolean%
When this method returns, if the conversion succeeded, contains true if value is equivalent to Boolean. . :: . TrueString or false if value is equivalent to FalseString. If the conversion failed, contains false. The conversion fails if value isnull Nothing nullptr a null reference (Nothing in Visual Basic) or is not equivalent to the value of either the TrueString or FalseString field.
The TryParse method is like the Parse method, except the TryParse method does not throw an exception if the conversion fails.
The value parameter can be preceded or followed by white space. The comparison is case-insensitive.
The following example calls the TryParse 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 Main()
Dim values() As String = { Nothing, String.Empty, "True", "False",
"true", "false", " true ", "0",
"1", "-1", "string" }
For Each value In values
Dim flag As Boolean
If Boolean.TryParse(value, flag) Then
Console.WriteLine("'{0}' --> {1}", value, flag)
Else
Console.WriteLine("Unable to parse '{0}'.",
If(value Is Nothing, "<null>", value))
End If
Next
End Sub
End Module
' The example displays the following output:
' Unable to parse '<null>'.
' Unable to parse ''.
' 'True' --> True
' 'False' --> False
' 'true' --> True
' 'false' --> False
' ' true ' --> True
' Unable to parse '0'.
' Unable to parse '1'.
' Unable to parse '-1'.
' Unable to parse 'string'.
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) {
bool flag;
if (Boolean.TryParse(value, out flag))
Console.WriteLine("'{0}' --> {1}", value, flag);
else
Console.WriteLine("Unable to parse '{0}'.",
value == null ? "<null>" : value);
}
}
}
// The example displays the following output:
// Unable to parse '<null>'.
// Unable to parse ''.
// 'True' --> True
// 'False' --> False
// 'true' --> True
// 'false' --> False
// ' true ' --> True
// Unable to parse '0'.
// Unable to parse '1'.
// Unable to parse '-1'.
// Unable to parse 'string'.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.