Trace.Fail Method (String, String)


Emits an error message, and a detailed error message.

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

Public Shared Sub Fail (
	message As String,
	detailMessage As String


Type: System.String

A message to emit.

Type: System.String

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

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

.NET Framework
Available since 1.1
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