COM Interoperability

BrianWren · January 24th, 2005, 05:51 PM

In a Microsoft knowledge base article (http://support.microsoft.com/?kbid=813809), I was led to use the following code:

Code:

Public Interface _clsOracleDisEmail
    Property ToName() As String
    Property ToAddress() As String
    Property FromName() As String
    Property FromAddress() As String
    Property CC_Name() As String
    Property CC_Address() As String
    Property Subject() As String
    Property Message() As String
    Sub Send(ByRef c As ADODB.Connection)
End Interface

<ClassInterface(ClassInterfaceType.None)> _
Public Class clsOracleDisEmail : Implements _clsOracleDisEmail

But âClassInterfaceâ in â<ClassInterface(ClassInterfaceType.None)>â generates an error stating that it is an unknown type.

I have seen scads of documentation today in researching this, all of which gives just this same syntax.

What [u]is</u> the deal? How is this attribute supposed to be used, if its identity doesnât exist, yet its identity needs to exist?

jaucourt · January 27th, 2005, 05:47 AM

You're almost there; you just need to add a

Code:

Imports System.Runtime.InteropServices

statement at the top of your code file, above the interface declaration.

Alternatively, you could do

Code:

<System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)> _
Public Class clsOracleDisEmail
    Implements _clsOracleDisEmail

On a small, very pedantic note, Microsoft recommended best practice is for your interfaces to start with and I, so instead of having _clsOracleDisEmail you'd have something like IOracleDisEmail. However, it's your code so you do what you like!

Also, to get rid of all compiler warnings, I had to add a reference to ADODB, because of the ADODB.Connection parameter in the Send method.