Using a c# .net object in an Excel VBA form

Question

Hi

I have a .net object that I want to use in Excel. I have an existing VBA script that i need to alter to call this the object from. I have then converted the object to a TLB. I've not really touched on this area before so any help will be appreciated.

I have created an interface

[Guid("0F700B48-E0CA-446b-B87E-555BCC317D74"),InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface IOfficeCOMInterface
{

    [DispId(1)]
    void ResetOrder();
    [DispId(2)]
    void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress);
}

I have also created an class that inherits that object.

[ClassInterface(ClassInterfaceType.None), ProgId("NAMESPACE.OfficeCOMInterface"), Guid("9D9723F9-8CF1-4834-BE69-C3FEAAAAB530"), ComVisible(true)]
public class OfficeCOMInterface : IOfficeCOMInterface, IDisposable
{
 public void ResetSOPOrder()
    {

    }
public void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress)
    {

        try
        {
            SalesOrder.AmendDeliveryAddress(PostalName, AddressLine1, AddressLine2, AddressLine3, AddressLine4, PostCode);

            MessageBox.Show("Delivery address set");
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

I can't access the object methods apart from dispose. Is there anything i need to do?

Answer 1

The following steps should work:

1. Compile your DLL.
2. Use regasm /tlb (or regasm /codebase /tlb, if you don't want to put your C# DLL into the GAC) to create a TLB and register it as a COM object.

3. Instantiate your object in Excel VBA, just like you would instantiate any other COM object. To do this, you can either:

   • use early binding: add a reference to your tlb in Excel and then use Set myObject = New NAMESPACE.OfficeCOMInterface or
   • use late binding, which does not require a reference: Set myObject = CreateObject("NAMESPACE.OfficeCOMInterface")

   The first option is easier for development, the second option is (often) easier for deployment.

4. Use your object in VBA: myObject.ResetSOPOrder.