C#

private async void Form1_Load(object sender, EventArgs e)
       {
           await Task.Run(() =>
           {
               LoadMyCombo();
           });

       }

private async void LoadMyCombo()
       {

           OleDbConnection con = new OleDbConnection(conex);
           string strSQL = "select  * from Customers order by cust_name";
           try
           {

               con.Open();
               OleDbDataAdapter adapter = new OleDbDataAdapter(new OleDbCommand(strSQL, con));
               DataSet ds = new DataSet();
               adapter.Fill(ds);

               mycombo.DataSource = ds.Tables[0];
              mycombo.ValueMember = "code";
               mycombo.DisplayMember = "cust_name";

           }
           catch (System.Exception erro)
           {
               MessageBox.Show("Error.... " + erro.Message);
           }

Hello,

I have a dll created with delphi language (Borland Delphi 7) which thus contains functions in delphi which I would like to use in C# under Visual Studio 2017. It is a native dll.
I want to use for example the GENERATE_FILE function contained in test.dll.

Delphi code :
procedure GENERATE _FILE(Path, Input_File : AnsiString); stdcall; 


procedure GENERATE _FILE(Path, Input_File : AnsiString); stdcall;
var

begin
…
GENERATE_CALC(Path_And_File, CRC32, Total, err);
…
end;


In C#, I want to use the function GENERATE_FILE contained in test.dll but what is the type of the parameters Path and Input_File in C# ?

Below is an example of C# code I made to use test.dll in delphi in C#. I set string as a type for parameters of the function GENERATE_FILE.

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

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

I added the test.dll in Visual Studio by right clicking on the project then add an existing element, then, in the properties of the test.dll, I put "Content" in Generation action and I put "Always copy "(output directory). When I run the solution, I have the test.dll in bin\Debug.

But when I test this program, I get the following error at the line that contains:
GENERATE_FILE(@"C:\Users", "file.txt");

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 think the issue is about the type of parameters in the function GENERATE_FILE. What are the type equivalents between delphi and C# for the function GENERATE_FILE ?

Thank you for your help.