Writes information about the trace to the trace listeners in the Listeners collection if a condition is true.

Overload List

Writes the value of the object's ToString method to the trace listeners in the Listeners collection if a condition is true.

[Visual Basic] Overloads Public Shared Sub WriteLineIf(Boolean, Object)

[C#] public static void WriteLineIf(bool, object);

[C++] public: static void WriteLineIf(bool, Object*);

[JScript] public static function WriteLineIf(Boolean, Object);

Writes a message to the trace listeners in the Listeners collection if a condition is true.

[Visual Basic] Overloads Public Shared Sub WriteLineIf(Boolean, String)

[C#] public static void WriteLineIf(bool, string);

[C++] public: static void WriteLineIf(bool, String*);

[JScript] public static function WriteLineIf(Boolean, String);

Writes a category name and the value of the object's ToString method to the trace listeners in the Listeners collection if a condition is true.

[Visual Basic] Overloads Public Shared Sub WriteLineIf(Boolean, Object, String)

[C#] public static void WriteLineIf(bool, object, string);

[C++] public: static void WriteLineIf(bool, Object*, String*);

[JScript] public static function WriteLineIf(Boolean, Object, String);

Writes a category name and message to the trace listeners in the Listeners collection if a condition is true.

[Visual Basic] Overloads Public Shared Sub WriteLineIf(Boolean, String, String)

[C#] public static void WriteLineIf(bool, string, string);

[C++] public: static void WriteLineIf(bool, String*, String*);

[JScript] public static function WriteLineIf(Boolean, String, String);

Example

[Visual Basic, C#, JScript] The following example creates a TraceSwitch named generalSwitch. This switch is set outside the code sample.

[Visual Basic, C#, JScript] If the switch is set to the TraceLevel Error or higher, the example outputs the first error message to the Listeners. For information on adding a listener to the Listeners collection, see the TraceListenerCollection class.

[Visual Basic, C#, JScript] Then, if the TraceLevel is set to Verbose, the example outputs the second error message and the category on the same line as the first message. The second message is followed by a line terminator.

[Visual Basic, C#, JScript] Note   This example shows how to use one of the overloaded versions of WriteLineIf. For other examples that might be available, see the individual overload topics.

[Visual Basic] 
' Class-level declaration.
' Create a TraceSwitch.
Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")

Public Shared Sub MyErrorMethod(category As String)
    ' Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ")
    
    ' Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, _
        "My second error message.", category)
End Sub


[C#] 
// Class-level declaration.
 // Create a TraceSwitch.
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");
 
 static public void MyErrorMethod(String category) {
    // Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ");
 
    // Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, "My second error message.", category);
 }


[JScript] 
// Create a TraceSwitch.
var generalSwitch : TraceSwitch = new TraceSwitch("General", "Entire Application")

function MyErrorMethod(myObject : Object, category : String){
  // Write the message if the TraceSwitch level is set to Verbose.
  Trace.WriteLineIf(generalSwitch.TraceVerbose, myObject.ToString() + " is not a valid object for category: ", category)
  
  // Write a second message if the TraceSwitch level is set to Error or higher.
  Trace.WriteLineIf(generalSwitch.TraceError, " Please use a different category.")
}

[C++] No example is available for C++. To view a Visual Basic, C#, or JScript example, click the Language Filter button in the upper-left corner of the page.

See Also

Trace Class | Trace Members | System.Diagnostics Namespace