AddressOf

This VB.NET operator enables delegate functions. With it we reference a method and use it as the implementation for a delegate.

Operator syntax

We use the name of a function and specify it where a delegate is required. We can use AddressOf to reference a function instead of a lambda.

Example

This program introduces the IsThreeLetters Function, which receives a String and returns a Boolean. This Function is used as a delegate. In Main we create a List and add 3 values to it.

Module Module1
    Function IsThreeLetters(ByVal value As String) As Boolean
        Return value.Length = 3
    End Function

    Sub Main()
        Dim list As List(Of String) = New List(Of String)
        list.Add("mouse")
        list.Add("horse")
        list.Add("dog")

        Dim value As String = list.Find(AddressOf IsThreeLetters)
        Console.WriteLine(value)
    End Sub
End Module
dog

Discussion

In the C# language, you do not need AddressOf. Instead, you can use the method name directly as the delegate. The AddressOf operator may be less confusing.

Summary

The AddressOf operator references an existing Function and turns it into a delegate. We do not need to use lambda expression syntax. We can use existing functions.