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Delegate.Combine Method (Delegate, Delegate)

Concatenates the invocation lists of two delegates.

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

public static Delegate Combine(
	Delegate a,
	Delegate b


Type: System.Delegate

The delegate whose invocation list comes first.

Type: System.Delegate

The delegate whose invocation list comes last.

Return Value

Type: System.Delegate
A new delegate with an invocation list that concatenates the invocation lists of a and b in that order. Returns a if b is null, returns b if a is a null reference, and returns a null reference if both a and b are null references.


Both a and b are not null, and a and b are not instances of the same delegate type.

The invocation list can contain duplicate entries; that is, entries that refer to the same method on the same object.

Combine is useful for creating event handlers that call multiple methods each time an event occurs.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0