Class name conflicts in C# and managed C++ dll in VS 2003

Question

I created a project in .net 2003. In this project the c# code will call a managed dll which is built by C++. In the dll it defines some classes whose names conflict with the classes from .net framework. For example: Stream Array in C++ dll and System.IO.Stream System.Collections.Array in C#. So when i compile the project all the c# code must include the namespace like System.IO.Stream. It is grotty and it is more important that the c# code has been written before the C++ dll and it means enormous and boring work to change the c# code. I have tried to find and set the corresponding compile options to overcome this problem. But nothing works. Please help me and any suggestions are appreciated!

Alan · Answer

It hadn't occured to me that it might be a 'mixed mode' Managed C++ dll. Anyway I'm pleased that you've solved it now :-)

ken du · Answer

Thanks for your help. I have solved the problem from the msdn. http://support.microsoft.com/?scid=kb%3Ben-us%3B822330&x=13&y=12 Adding the compiler option /d1PrivateNativeTypes in vs 2003 is ok. Best regards.

ken du · Answer

I have read some topics about the class visibility in MSDN. The default visibility for a class is private which means that it is visible only within the assembly. But Array is a unmanaged class how to control its visibility to the outside?

ken du · Answer

The code in c++ is just like the following : public __gc class OutClass { Array arr; ... } class Array { } Array is an internal class while OutClass is a public class. I only want to expose OutClass to the c# code but not Array. Since Array is not defined by the keyword __gc why is it still exposed to the outside c#? How can i hide the Array by recompiling the c++ dll ? Thanks a lot!

ken du · Answer

Thanks for your quick and good answers. The way you adviced is useful. But I have another question that all the conflict classes in C++ dll will not be used in c# code. Could I define all the conflict classes as internal classes which will not seen by the c# code? I can access the c++ code. Thanks in advance.

Alan · Answer

Sorry but to the best of my knowledge there are no compiler options in VS 2003 which would help with this problem. However if you have access to the Managed C++ source code then you could simply place everything within a namespace (CPPTypes say) and rebuild the dll. Them from the C# side you could use some 'using' aliases to distinguish between the similarly named types. For example: using System.IO; using System.Collections; using CPPTypes; using Stream = System.IO.Stream; using CPPStream = CPPTypes.Stream; using Array = System.Array; using CPPArray = CPPTypes.Array; That way you wouldn't need to fully qualify the .NET framework Stream Array etc from your code.

ken du · Answer

The classes in C++ are defined in a global level. Is there any other way like setting compiler options in the c++ project or c# project? Because it succeeds in vs 2005 with some different compiler options which are not supported in vs 2003. Thanks in advance.

Alan · Answer

Are the managed C++ classes themselves within a namespace or were they all defined at global level?