Debug.Fail Method (String, String)

Emits an error message and a detailed error message.

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

[ConditionalAttribute("DEBUG")]
public static void Fail(
	string message,
	string detailMessage
)

Parameters

message
Type: System.String

A message to emit.

detailMessage
Type: System.String

A detailed message to emit.

The default behavior is that the DefaultTraceListener outputs the message to a message box when the application is running in user interface mode and to the TraceListener instances in the Listeners collection.

NoteNote

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 removing one from, the Listeners collection.

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

catch (Exception) {
    Debug.Fail("Invalid value: " + value.ToString(), 
       "Resetting value to newValue.");
    value = newValue;
 }

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

switch (option1) {
    case MyOption.First:
       result = 1.0;
       break;

    // Insert additional cases. 

    default:
       Debug.Fail("Unknown Option " + option1, "Result set to 1.0");
       result = 1.0;
       break;
 }

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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