Accessing a C++ .lib library from c#

Question

I have a c++ library file (.lib). How can I access the functions within it from C#? I have read that I could wrap the library file in a c++ dll and expose the functions that way. Is that the only way? I am not the owner of the code, so my options are limited.

Answer 1

Wrap the C++ lib with a C++/CLI assembly.

C++/CLI allows you to mix managed and unmanaged code, serving as a bridge between C# and native C++. It's actually very straightforward and relatively easy to do, although it can get tedious if you have a lot of classes/functions to wrap.

Here is one example.

Answer 2

You can not access a c++ library file (.lib) directly. The best way is to have an unmanaged wrapper around your unmanaged code. Reference DllImportAttribute .

There's a good example of it's usage in the MSDN help document:

using System;
using System.Runtime.InteropServices;

class Example
{
    // Use DllImport to import the Win32 MessageBox function.
    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
    public static extern int MessageBox(IntPtr hWnd, String text, String caption, uint type);

    static void Main()
    {
        // Call the MessageBox function using platform invoke.
        MessageBox(new IntPtr(0), "Hello World!", "Hello Dialog", 0);
    }
}

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Also note: You can have a managed c++ wrapper around your c++ library, but it's better to write your wrapper in unmanaged c++ code.

Answer 3

You can convert lib to dll with this cmd script . After that you'll be able to use DllImport to access its functions. But you had to modify it a bit to make this script work.