Failed to call unmanaged functions in C++ dll compiled in Visual 6.0

[trantanm]

Hi everybody,
I failed to call unmanaged functions in C++ dll from C# application.
If I compile and produce the C++ dll file in .NET environment, I can
call them from C#. Is the reason that the C++ dll file compiles on the
different platform? Is there any way to correct the problem?
Appreciate your help.
IfOnce.

 

[Nicholas Paldino [.NET/C# MVP]]

Can you show some of your code? Without seeing what exactly you are
trying to do, it's very difficult to say.

 

[trantanm]

Nicholas,
Thank you for your response.


My DriverFunctionTests.cpp has the following:
extern "C" __declspec(dllexport) void __stdcall InitDriver( unsigned
short uChannel )
{
pclDriver = new ClDriverWrap( uChannel );
}

My DataWrapper.cs has these:
[DllImport("DriverLibrary.dll")]
public static extern void InitDriver( ushort uChannel );

[DllImport("DriverLibrary.dll")]
public static extern void ResetDriver();

[DllImport("DriverLibrary.dll")]
public static extern bool IsDriverLoaded( ushort uChannel,
[In(),arshalAs(UnmanagedType.LPArray)] byte [] strMessage );

And my DriverTester.cs has:
static void Main()
{
try
{
Application.Run(new Driver_Tester());
}
catch( Exception ex )
{
MessageBox.Show( "Driver_Tester.Main(): " + ex.Message );
}
}
private void Driver_Tester_Load(object sender, System.EventArgs e)
{
ClDataWrapper.InitDriver(0);
}

To compile the whole solution in .NET, I put DriverFunctionTests.cpp in
the project DriverLibrary, and I put DataWrapper.cs and DriverTester.cs
in anther project DriverTester. After compiling, I copy and paste the
DriverLibrary.dll to the Debug folder of the project DriverTester.

If I compile this solution in .NET, the code works great. However, if I
remove the project DriverLibrary, compile DriverFunctionTests.cpp in
Visual Studio 6.0, copy and paste the dll file, then the C# code throws
the exception saying "Unable to load the DriverLibrary.dll".

Appreciate your help.