.netcomvb6early-binding

Forcing the VB6 compiler to use early binding when calling a .net com dll

I have a com dll written in c# After running Regasm I can call this dll from VB6, referencing the com dll. In VB6 I have intellisense available.

However when I press F5 to compile the compiler does not catch any mistakes in calling the com dll. It must be using late binding.

How can I get it to use early binding?

The interface is declared 

using System.Runtime.InteropServices;   
namespace combridge    
{
[Guid("2f4b6041-91e3-4d9f-a9f5-9bd4adfd1789")]  
[ComVisible(true)]  
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
    public interface IBridge    
     {
      // methods go here
     }    
  }

The main class is declared

[Guid("085777fa-9397-4cfd-843a-85ececb86789")]
[ProgId("companyname.ComBridge")]
[ClassInterface(ClassInterfaceType.None)]
[ComVisible(true)]
public class BridgeImplementation : IBridge
{
    #region Public Implementation

    [DispId(1)]
    [ComVisible(true)]
    public string EchoTest(string message)
    {
        return string.Format("Echo '{0}' at {1:T}", message, DateTime.Now);
    }

 // etc

[update]

In the VB6 project I reference the tlb file which I create using 

c:\WINDOWS\Microsoft.Net\Framework\v4.0.30319/regasm /verbose /codebase /tlb:CommBridge.tlb ComBridge.dll

In the VB6 I create the object using 

Dim o As BridgeImplementation
Set o = New BridgeImplementation
o.EchoTest  // executes
o.NonExistantFunction // run time error
Solution

  • Above the interface declaration I replaced 

    [InterfaceType(ComInterfaceType.InterfaceIsDual)]

    with 

    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]

    and it solved the problem