What is HRESULT and what is its role in error management?
As mentioned previously, .NET uses a structured exception handling approach for indicating, and reacting to, both anticipated and unanticipated error conditions. This is not the case in Visual Basic 6.0. (Although the OnError handler provides a process that can be considered similar to exception handling, it does not behave the same way.) Because interoperability between Visual Basic .NET and Visual Basic 6.0 is achieved using COM-based mechanisms, there is an inherent value, named HRESULT, which is passed back and forth between the Visual Basic 6.0 code and the .NET assembly. Even though this happens behind the scenes, it is still there. In Visual Basic 6.0, this value can be accessed through the Err.Number property. In Visual Basic .NET, this value is treated differently depending on whether or not the original exception is a standard exception.
