Using Visual Basic 6 with Visual Basic .NET COM Interop

Short Description
This chapter focuses on making your Visual Basic 6 and Visual Basic .NET … make up your application are based on COM, your Visual Basic .NET applica- …

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Content
175
Using Visual Basic 6
with Visual Basic .NET:
COM Interop
This chapter focuses on making your Visual Basic 6 and Visual Basic .NET
applications work together. The mechanism that makes interoperability
between the two products possible is known as COM interop. We’ll start by
looking at the various ways you can create or use existing components that
communicate across COM and .NET component boundaries. We’ll also show
you how to debug across calls between Visual Basic 6 and Visual Basic .NET
authored components. Finally, we’ll discuss the role of binary compatibility in
Visual Basic .NET.
If you’ve been creating multitiered applications using Visual Basic 6, your
application has likely evolved into a large system spanning multiple components.
Let’s say, for example, that you have an application composed of a Visual
Basic standard EXE front end containing ActiveX controls talking to a middletier
Visual Basic DLL. The Visual Basic DLL in turn talks to a back-end SQL
Server database. Upgrading such an application to Visual Basic .NET in one
shot is nearly impossible. This is where COM interop swoops in to save the day.
COM interop allows you to upgrade one component at…