In VBA, C# dll says there is no entry point

Question

I looked at other posts and couldn't find the solution.

I am trying to use C# dll I created in VBA code without having to add reference.

In my VBA code, I declared:

Public Declare Function message Lib "path_to_my_dll" _
 (ByVal message As String) As String


Sub Test()

Dim hello As String

    hello = message("hi!!")
    Debug.Print hello

End Sub

I get an error saying entry point for my dll couldn't be found.

The C# Code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;

namespace DLLImport
{
    public class Class1
    {
        [DllImport("DLLImport", EntryPoint = "Run")]
        extern string Run(string message)
        {
            return message;
        }
    }
}

Thank you in advance for your help!!

Answer 1

You might want to use InteropServices to make a COM Visible DLL

using System.Runtime.InteropServices;   

[InterfaceType(ComInterfaceType.InterfaceIsDual)]
[Guid("your-GUID-1")]
public interface _Visible_Methods
{
    //--------< _Visible_Methods >--------

    //*visible COM Methods of this Control under Office,Excel, Word

    string get_Hello();

    //--------</ _Visible_Methods >--------
}

Source: https://codedocu.com/Net-Framework/Controls/COM-ActiveX/Create-C_hash_-COM-Control-for-Office?2382