I suggest that you can use WM_COPYDATA to send data between the different processes. To achieve this, you can use SendMessage function in C# through P/Invoke. And there are several references on this issue:
Could you please cover your VB6.0 application in more details? Is it a control DLL and you want to use it in your C# application or it is a single application?
Both C# and VB6.0 applications are standalone windows applicatios(no DLL). Both will be run separately on the same machine. I need to pass some string data to vb6.0 application.
I suggest that you can use WM_COPYDATA to send data between the different processes. To achieve this, you can use SendMessage function in C# through P/Invoke. And there are several references on this issue: