How to declare callback function and pass as paramater to function

[alanlau]

I'm using a function in a third-party DLL library that takes a callback function as a parameter. The library was written and C#, but it seems to be perfectly compatible with VB. The only problem I'm having is figuring out how to pass one of the functions a callback function. Here is how the function is declared:

public void DownloadFile(string path, Stream output, Action<ulong> downloadCallback = null)

So I'm assuming it wants a function with a single unsigned long parameter. Any ideas?

 

[JohnH]

So I'm assuming it wants a function with a single unsigned long parameter

Yes, pass the method with AddressOf operator. Method signature must match Action(Of T) delegate where T is type ULong, in other words a Sub with one Ulong parameter.
AddressOf Operator (Visual Basic)
Action(T) Delegate (System)

 

[alanlau]

That did the trick. Thanks.