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Trace.Fail Method (String, String)

Emits an error message, and a detailed error message.

Namespace: System.Diagnostics
Assembly: System (in system.dll)

<ConditionalAttribute("TRACE")> _
Public Shared Sub Fail ( _
	message As String, _
	detailMessage As String _
Dim message As String
Dim detailMessage As String

Trace.Fail(message, detailMessage)
/** @attribute ConditionalAttribute("TRACE") */ 
public static void Fail (
	String message, 
	String detailMessage
public static function Fail (
	message : String, 
	detailMessage : String
Not applicable.



A message to emit.


A detailed message to emit.

The default behavior is for the default trace listener to output the message parameter and the detailedMessage parameter to a message box when the application runs in user-interface mode, and to the TraceListener instances in the Listeners collection.


The display of the message box is dependent on the presence of the DefaultTraceListener. If the DefaultTraceListener is not in the Listeners collection, the message box is not displayed. The DefaultTraceListener can be removed by the <clear> Element for <listeners> for <trace>, the <remove> Element for <listeners> for <trace>, or by calling the Clear method on the Listeners property (System.Diagnostics.Trace.Listeners.Clear()).

You can customize this behavior by adding a TraceListener to, or by removing one from, the Listeners collection.

The following example uses the Fail method to print a message during exception handling.

    Trace.Fail("Invalid value: " & value.ToString(), _
        "Resetting value to newValue.")
    value = newValue
End Try

catch (System.Exception exp) {
    Trace.Fail("Invalid value: " + System.Convert.ToString(value),
        "Resetting value to newValue.");
    value = newValue;

catch(e : Exception)
    Trace.Fail("Invalid value: " + value.ToString(), 
       "Resetting value to newValue.")
    value = newValue

You can also use the Fail method in a switch statement.

Select Case option1
    Case OptionConsts.First
        result = 1.0
    ' Insert additional cases.
    Case Else
        Trace.Fail("Unsupported option " & option1, "Result set to 1.0")
        result = 1.0
End Select

switch (option) { 
    case Option.first :
        result = 1.0;
    // Insert additional cases.
    default :
        Trace.Fail("Unsupported option " + option, "Result set to 1.0");
        result = 1.0;

    case 1:
        result = 1.0
  // Insert additional cases.
        Trace.Fail("Unknown option: " + option, "result set to 1.0")
        result = 1.0

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

XNA Framework

Supported in: 1.0