What are the most common upgrade issues that produce run-time errors?
• Changes to User-Defined Types. User-defined types can be defined in Visual Basic 6.0 using the Type keyword. All the members included in a Type block are automatically initialized by the Visual Basic 6.0 runtime. • Changes to Null and IsNull. Null and IsNull have different behaviors in Visual Basic .NET than in Visual Basic 6.0. The upgrade wizard detects the usage of Null and IsNull. Null is upgraded to the closest value available in Visual Basic .NET, which is System.DBNull.Value. However, Visual Basic .NET does not support propagating the Null value. This will result in behavior differences that produce run-time errors. • Changes to Array Indexing. In Visual Basic 6.0, it is possible to create arrays whose lower index bound is a value other than 0. In Visual Basic .NET, all arrays must have a lower index bound of 0. The upgrade wizard ensures all arrays have a lower bound of 0. However, if the source code relies on the calculated size of arrays, the behavior of the array code in t
