How does passing of user-defined types to API functions differ in .NET?
When you pass a Visual Basic 6.0 user-defined type to an API function, Visual Basic passes a pointer to the memory that contains the user-defined type. The API function sees the members of the user-defined type in the same order that they were declared in Visual Basic. However, this is not the case for Visual Basic .NET. If you declare a user-defined type, the order of the members is not guaranteed to stay the same in the code. The common language runtime (CLR) may reorganize the members of a user-defined type in a way that is most efficient for the user-defined type to be passed to a function. To guarantee that the members are passed exactly as declared in the code, you need to use marshaling attributes. For example, if your code is calling an API function named MyFunction (written in C or C++), that takes a 2-byte Boolean type (VARIANT_BOOL) parameter, you can use the MarshalAs attribute to specify the parameter type that the API function expects. Usually, a Boolean parameter is pass
