AddressOf Operator | VB.NET Language in a Nutshell

AddressOf Operator

Syntax

 AddressOf   procedurename

procedurename (required): The name of a procedure that is referenced by the procedure delegate

Description

The AddressOf operator returns a procedure delegate instance that references a specific procedure.

The AddressOf operator is used in the following situations:

If a parameter to a procedure (a VB procedure or a Win32 API function) requires a function pointer (the address of a function), then we can pass the expression:
```
 AddressOf functionname 
```
where functionname is the name of the function. This function is called a callback function .
AddressOf is also used to create delegate objects, as in:
```
 delg = New ADelegate(AddressOf obj.AMethod) 
```
AddressOf is used to bind event handlers to events through the AddHandler statement:
```
 AddHandler Form1.Click, AddressOf Me.Form1Click 
```

Examples of all three applications of AddressOf can be found in Section 7.1 in Chapter 7.

VB.NET/VB 6 Differences

In VB 6, the AddressOf operator can only be used in a call to a Windows API function. Moreover, the argument passed to AddressOf must be the name of a procedure in a standard code module. However, in VB.NET these restrictions no longer apply.