How to import dll in c# that can be accessed by [DllImport]

The steps are as follows:

1. Compile your C# DLL (You may use Visual Studio for this).
2. Decompile your C# DLL using ILDASM.EXE.
3. Expose/Export your methods (Details to follow).
4. Recompile your C# DLL from the modified MSIL code using ILASM.