Hi,
DDE depends on windows messaging. This means you need to use in your C# code SendMessage function that you can find in win32 api.
You can import this function to your C# code using this part of code.
[DllImport("user32.dll")]
public static extern int SendMessage(
int hWnd,
uint Msg,
long wParam,
long lParam
);
But of course before use this method you need get handle of the window you want to send message to. You can do it either call FindWindow function from win32 api:
[DllImport("user32.dll")]
public static extern IntPtr FindWindow(string className, string windowName);
or
you can use similar code to the following one:
Process[] processes = Process.GetProcessesByName("YourProcessName");
foreach (Process process in processes)
{
IntPtr windowHandle = p.MainWindowHandle;
}
Good luck,
Alexey