C# using SendMessage, problem with WM_COPYDATA

Question

I\'ve been spending a few days (or more) trying to get this to work.

The application at hand is FTPRush, and I know there is a cmd line application call

Answer 1

My Definitions have

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, ref COPYDATASTRUCT lParam);

public struct COPYDATASTRUCT {
  public int cbData;
  public IntPtr dwData;
  [MarshalAs(UnmanagedType.LPStr)] public string lpData;
}

var cds = new Win32.COPYDATASTRUCT {
                                           dwData = new IntPtr(3),
                                           cbData = str.Length + 1,
                                           lpData = str
                                         };
Win32.SendMessage(ftprush, Win32.WM_COPYDATA, IntPtr.Zero, ref cds);

Of course, make sure that str is null terminated "\0"

Alternatively a definition given by PInvoke.NET is

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, StringBuilder lParam);
//If you use '[Out] StringBuilder', initialize the string builder with proper length first.