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Trace.WriteLine Method (Object, String)

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

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

[ConditionalAttribute("TRACE")]
public static void WriteLine(
	Object value,
	string category
)

Parameters

value
Type: System.Object

An Object whose name is sent to the Listeners.

category
Type: System.String

A category name used to organize the output.

By default, the output is written to an instance of DefaultTraceListener.

The category parameter can be used to group output messages.

This method calls the WriteLine method of the trace listener.

The following example creates a TraceSwitch named generalSwitch. This switch is set outside the code sample.

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.

Then, if the TraceLevel is set to Verbose, the example outputs the second error message on the same line as the first message. The second message is followed by a line terminator.

// Class-level declaration. 
 // Create a TraceSwitch. 
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");

 static public void MyErrorMethod(Object myObject, String category) {
    // Write the message if the TraceSwitch level is set to Error or higher. 
    if(generalSwitch.TraceError)
       Trace.Write("Invalid object for category. ");

    // Write a second message if the TraceSwitch level is set to Verbose. 
    if(generalSwitch.TraceVerbose)
       Trace.WriteLine(myObject, category);
 }

.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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