如何使用C＃创建非托管DLL？

Question

I want to create a DLL using C#, which can be then called from VBA in the following manner -

Private Declare Function invokePath Lib "\\shared_computer\Projects\somedll\myDLL.dll" (ByVal strUName As String, ByVal strSFile As String) As String

The idea is, if the path of the DLL is changed I need to only update the path in the Private Declare function line....

I have searched a lot for it, and also not sure whether this arrangement is possible - where we can call a DLL function from a network path without referencing or registering.

Answer 1

Actually you can. Check out unmanagedexports It is a complete walk-through and you'll be able to create entry points like this:

[DllExport("GenerateSomehting", CallingConvention = CallingConvention.Cdecl)]
public static int GenerateSomehting(int somevalue, ref IntPtr pointer)

and call it just like any other unmanaged dll.

[DllImport("MyGenerator.dll", CallingConvention = CallingConvention.Cdecl)]
static extern int GenerateSomehting(int somevalue, ref IntPtr pointer);

Answer 2

You can not create unmanaged DLLs with C#, as C# is a .NET only language. Use C++.

The only way to use a .NET DLL from unmanaged code (for example VBA) is to use COM interop.

Answer 3

Check P/Invoke here, The article contains a useful table of how to translate managed to unmanaged types, short code examples (in C#), tips and a list of resources.

Essential P/Invoke

Answer 4

C# Dll cannot export functions that can be called by any other non-CLR code.

This is not possible.