How to use a dll encoded in delphi from C# in Visual Studio

Question

Hello,

I have a dll coded in delphi language which thus contains functions in delphi which I would like to use in C# under Visual Studio 2017.

I want to use for example the GENERATE function contained in test.dll.

Below is an example of C # code I made to use test.dll in delphi in C#.

namespace AppTest
{
    Public class Program
    {
        [DllImport("test.dll", CharSet = CharSet.Ansi)]
        public static extern bool GENERATE(string pathfilename);

        static void Main(string[] args)
        {
            GENERATE(@"C:\Users\file.txt");
        }
    }
}

 

But when I test this program, I get the following error:

System.DllNotFoundException: 'Unable to load DLL' test.dll ': The specified module could not be found. (Exception from HRESULT: 0x8007007E) '

How to solve this problem ?

I placed test.dll in the folder that contains the C # source files.

How C# is able to read a dll in delphi if Visual Studio does not know delphi?

Thank you for your help.