Import old DLL to C# .Net

[Reza Shojaee]

Hi everybody I have old dll(s) that implemented with Visual Basic 6.0 and Borland Delphi 6.0 and Visual C++ 6.0 I haven't the source of these dlls, So I want to know how can import these dll to C# .Net as a reference.

Best Regards, Reza Shojaee

[Calla]

If it's a COM component you can just add it from the COM tab and let VS create the Interop.

[Reza Shojaee]

I tried with COM tab but VS doesn't accept it

Best Regards, Reza Shojaee

[Vimalsoft Pty Ltd]

Do you receive some sort or Error ?

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[Dave Kreskowiak]

Then it's not a COM-based .DLL. You'll have to use P/Invoke to get at the functions it exposes. I hope you have all the documentation on the functions because, if you don't, you're going to find it nearly impossible to call the functions in the .DLL.

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Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007, 2008
But no longer in 2009...

[puromtec1]

You need to look up interop services. You can use tlbimp.exe to generate your interop if it is COM (which from the post above seems not to be the case). Otherwise, you can use the DLLImport attribute and reference the functions this way. You will find it tricky to figure out the proper types to use in the function signature, so you need to research a little. But, this is your start.

[DllImport("TheCplusplus.dll")]
static extern uint BTSeparateItems([In, MarshalAs(UnmanagedType.BStr)] string filePath, out object obj);