Wrapping C++ functions

[CJ1]

I'm trying to call a C++ function in a dll from a GUI I made with Winforms in VS.NET. I'm doing it something like this:

[DllImport("Data.dll")]
private static extern bool IsOpen();
...
static void Main(){
IsOpen();
//do something
}

The error I keep getting is
"Unable to find an entry point named IsOpen in DLL Data.dll"...?

Yes, try:

using System.Runtime.InteropServices;

[DllImport("Data.dll")]
private static extern bool CDataApp.IsOpen();

When looking for more information on this search for "PInvoke".