How to import C++ methods in C#

Question

Hi I have coded few methods in C++ language. These methods are to be used in C#.NET . I guess I need to convert the .CPP file(C++ code) into DLL and then import the methods in C#. Can any one give an idea how to convert .CPP file into DLL and then use that DLL in C#. Thanks.

Pranav Thakur · Answer

I have created an unmanaged C++ DLL and tried to call its method in C#.NET as : using System.Runtime.InteropServices; public partial class CDLL : System.Web.UI.Page { [DllImport(C:\Project1\TestProject\Debug\TestProject.dll EntryPoint = testMethod ExactSpelling = false CallingConvention = CallingConvention.Cdecl)] public static extern void testMethod(); protected void Page_Load(object sender EventArgs e) { testMethod(); } } After running the above code i am getting error like : Unable to find an entry point named 'testMethod' in DLL 'C:\Project1\TestProject\Debug\TestProject.dll'. Can any one suggest how to run the above code successfully. Thanks.

Sam Hobbs · Answer

If you need to have a type library then you don't want a regular DLL; you need a COM object. If your C++ project is a regular DLL project then you must use a DllImport attribute to call the function in the DLL.

Sam Hobbs · Answer

I doubt that you want to build a static library; a static library is not a DLL correct? You need to create a DLL project and the new project will have starter souce code. Be sure that the function you create has __declspec(dllexport) on it but the generated source codw will show how how to do that. Or you could create a COM object. That will require more time to learn but it will be more flexible.

Pranav Thakur · Answer

Thanks for your reply. I followed the steps as you suggested but I could not add the created DLL into my project as reference. I made a Win32 project and converted the exe(C++ code) into DLL. I opened a new Visual Studio C#.NET project and tried to include the above DLL but I am getting error as : A refernce to 'C:\application	est.dll' could not be added. No type libraries were found in the component.

Kirtan Patel · Answer

Friend  You need to make a Win32 Project and in the dialog that comes up choose DLL. Don't make a MFC DLL unless your specifically targeting MFC they aren't a normal DLL Check the radio button for Static Library. Paste All Your Code Hit compile You will Get DLL File :) if my answer helped you please check  Do you like this answer  :) if any problem occurred feel free to tell me :)