COM and .NET Interop - Part II

Out of curiosity, I have been working through some of my COM and .NET Interop issues, and most specifically, working with passing arrays between to / from a C# component from Visual Basic 6.0.  As my earlier post indicates, this is in response to a client’s desire to replace VB6 COM+ components with a .NET implementation in c# while minimizing changes to Classic ASP.  Here are some of my findings.  In cases for strongly-typed arrays, I used strings; loosely-coupled means object in .NET and variant in VB6.

 

• System.Array is not easily (not sure if it is possible) used with interop
• Single dimension, strongly-typed arrays are easily used with interop.  In my case, I used strings. However, when used as input parameters, they must be passed byref and zero indexed.
• Two dimension, strongly-typed arrays are easily used with interop.  They also have the same constraints as single dimension arrays (must be passed byref and must be zero indexed).
• Zero-indexed arrays could cause a ripple effect in COM client code and requires more investigation.