Using a C# dll in VB6

Using a C# dll in VB6

• BrandyR

  Digimonk,

  I tried it, but I still get the error "Invalid procedure call or argument.". In fact I also tried using this code:

  Dim Exceptionobj As Exception
  Set Exceptionobj = New Exception
  
  Errorob.ShowError(Exceptionobj)

  Can you figure it out why this is happening.

  Thanks,

  Frenz

  
  

  
  

• charliestrause

  Hi,

  Is it possiblt to include our own C# dll's to VB 6.0 pgm. The dll's contains more no.of user controls. I wish to use those user controls to our VB pgm. Can give the clear steps for this plz.

  Cheer.

  
  
  

• Dhanya

  You can create an extra class to map the ErrObject to your .NET dll:
  
  

  [ComVisible(true)] [Guid("80FA0002-4976-4226-A539-397BD93E9B6A")] [InterfaceType(ComInterfaceType.InterfaceIsDual)] public interface _ErrorObject { int ErrorCode { get; set; } string Message { get; set; } string Description { get; set; } string Source { get; set; } } [ComVisible(true)] [Guid("1EB825A6-ED23-4b17-9C62-0D54DDCD3DD9")] [ClassInterface(ClassInterfaceType.None)] public class ErrorObject : _ErrorObject { private int _errorCode; private string _message; private string _description; private string _source; public int ErrorCode { get { return _errorCode; } set { _errorCode = value; } } public string Message { get { return _message; } set { _message = value; } } public string Description { get { return _description; } set { _description = value; } } public string Source { get { return _source; } set { _source = value; } } public ErrorObject() { } }

  
  
  Usage:
  

  Private Sub Form_Load() Dim myVb6Error As New ErrObject Dim err As New ErrorObject err.ErrorCode = myVb6Error.ErrorCode err.Message = "My error" err.Description = myVb6Error.Description err.Source = myVb6Error.Source Errorob.ShowError (err) End Sub

  
  
  
  

• Tuhin

  Hi,

  Thanks! It works but now I have a small problem. In my class file (C#) there is a method defined as follows

  public void ShowError(Exception err)
  {

  ///code to be executed

  }

  Now in my vb code I have given as

  On Error GoTo Errorline

  'the code to be executed
  Errorline:

  Dim obj As New ErrObject
  Dim Errorob As Error.Test
  Set Errorob = New Error.Test
  Set obj = Err
  Errorob.ShowError (obj)
  End Sub

  Now I'm getting the error at Errorob.ShowError (obj) saying "Invalid procedure call or argument". How can I make this possible. Is it because the object "obj" in VB is not compatible with the "err" object in C#. I want to do this through the dll only. Please provide me with a solution.

  Thanks & Regards,
  Frenz

  
  

• Raphael Londner

  Frenz,
  
  The problem is that you are mixing up two different object types. The C# function is looking for a SystemException object, and the VB6 app is sending the VBA.Err object.
  
  What you need to do is to open the References dialog in VB6 by going to Project | References. Find 'mscorlib.dll' and check it, and click OK. In the VB6 code declare an object as a SystemException (which is a new type introduced by mscorlib.dll) and pass that.
  
  Dim Exception As SystemException
  Set Exception = New SystemException
  
  Errorob.ShowError(Exception)
  
  This should help. You don't get the IntelliSense autocompletion with the SystemException object, so you'll have to refer to the documentation to use its properties and methods.
  
  I hope this helps.
  
  digimonk
  
  

• pdesai

  Yep! it's possible... You just have to create your C# class and compile it to a dll, then use regasm.exe for assembly registration and typelib generation...
  
  regasm YourAssembly.dll /tlb:YourAssembly.tlb
  
  This command makes the appropriate registry entries and generates a typelib (.tlb) from the .NET assembly so that it can be referenced from VB 6 and just use the referenced library just as you would use a COM object.
  
  HTH,
  
  
• Using a C# dll in VB6