Passing UDTs to Classes

This article is based on Visual Basic 6. Find other Visual Basic 6 articles.

This is actually extremely simple to do - all you need to do is declare the method (be it a property, function or sub) to which you are passing the UDT as Friend - like this:

'-- In some module
Public Type myType
    x As Integer
    y As Integer
End Type

'-- In the class
Friend Function myFunction(foo As myType) As Integer
    myFunction = foo.x * foo.y
End Function

'-- Passing to the function
Dim foo As myType
foo.x = 10: foo.y = 100
Debug.Print myClassInstance.myFunction(foo) '-- Prints 1000 to Immediate window

Simple :-)

NOTE: This will only work when using the class from within the same project in VB. If compiled and used as a COM component, then any methods declared as 'Friend' will not appear. See MSDN on the topic of the Friend keyword:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbenlr98/html/vakeyFriend.asp