Symptoms
In a Microsoft Visual Basic .NET collection, you can add a member after a zero index by using the Add method, but the collection is one-based. However, when you add a member after a zero index, the member is added at the first index.
Note In a Microsoft Visual Basic 6.0 collection, you receive a “Subscript out of range” error when you try to add a member after a zero index by using the Add method.
Resolution
This bug occurs because the collection is implemented as an array with Empty placeholder to adjust for 1 based array as the value for the zero index. This collection implementation allows you to add a member after the zero index.