MarkLabel Method

ILGenerator.MarkLabel Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Marks the Microsoft intermediate language (MSIL) stream's current position with the given label.

Namespace:  System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

public virtual void MarkLabel(
	Label loc


Type: System.Reflection.Emit.Label
The label for which to set an index.


loc represents an invalid index into the label array.


An index for loc has already been defined.

A label cannot be defined more than once.

The following example demonstrates the use of MarkLabel to establish the location of a label that was defined earlier. Notice that the label is used in a call to the Emit(OpCode, Label) method overload before its location has been established.

This code is part of a larger example provided for the BeginExceptionBlock method.


// The finally block block displays a message on the TextBlock, if the 
// OutputBlock field has been set. Just as in the catch block, the following
// code tests whether the TextBlock is present, and skips the output if it is
// not present.
adderIL.Emit(OpCodes.Ldsfld, demoOutput);
adderIL.Emit(OpCodes.Brtrue_S, skipOutputInFinally);

// Append a constant string to the Text property of the TextBlock.
adderIL.Emit(OpCodes.Ldsfld, demoOutput);
adderIL.Emit(OpCodes.Ldsfld, demoOutput);
adderIL.Emit(OpCodes.Callvirt, getter);
adderIL.Emit(OpCodes.Ldstr, "Executing the finally block.\n");
adderIL.Emit(OpCodes.Call, concat2);
adderIL.Emit(OpCodes.Callvirt, setter);

// This is the end of the try/catch/finally block.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Windows Phone

© 2017 Microsoft