how do I access a method inside a class of unmanaged DLL from C#

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I need to invoke a method of a class in unmanaged dll written in C++.
e.g., DLL name: cast.dll
A class in cast.dll: parser
A function in parser class: castToObject(someVal as string)

For example here is how to access it in VB dynamically.

dim objCast
Set objCast = Server.CreateObject("cast.parser")
strCastedItem = objCast.castToObject("someValue")

I would like to access the castToObject method from C#.
Your help is highly appreciated.

Posted 24-Apr-14 19:04pm

teshman

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_Asif_ · Answer 1 · 2014-04-24T19:18:00

Solution 1

If you have had googled.... Anyway i have googled for you and found below urls. Might help u

steps on calling COM dll API into my c# code[^]

COM Interop Part 1: C Sharp Client Tutorial[^]

Posted 24-Apr-14 19:18pm

_Asif_

teshman · Answer 2 · 2014-04-25T02:59:00

Syed,

Thanks for the response. Actually, I did research and most of the search results point on using DLLImport which works perfectly if the DLL has a method to be invoked. None of them show how to invoke methods inside a class of that dll.

However, I did look at the links you've provided and as I said the first one that talks about using the DLLImport method didn't work for me because the function is in the co-clsss.

The other link could've been useful only if I know the GUID for the "parser" class inside the cast.dll. Since I don't know the GUID and also since there is no typlib for the com definition, I couldn't use the solution to solve my problem.