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POC# using SendMessage, problem with WM_COPYDATA
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copied!<p>I've been spending a few days (or more) trying to get this to work.</p> <p>The application at hand is <code>FTPRush</code>, and I know there is a cmd line application called <code>rush_cmdline.exe</code> which uses <code>SendMessage</code> to send requests to <code>FTPRush</code>.</p> <p>From debugging the <code>rush_cmdline.exe</code> I can see <code>lParam</code>, <code>wParam</code>, <code>Message</code> and <code>hWnd</code>.</p> <p>My code is as follows (using SendMessage, not SendMessageW):</p> <pre><code>[DllImport("User32.dll", EntryPoint = "FindWindow")] public static extern Int32 FindWindow(String lpClassName, String lpWindowName); [DllImport("USER32.DLL", EntryPoint= "SendMessage")] public static extern IntPtr SendMessage(int hWnd, int Msg, int wParam, IntPtr lParam); </code></pre> <p>And I've tried a another specification also:</p> <pre><code>[DllImport("User32.dll", EntryPoint = "SendMessage")] public static extern int SendMessage(int hWnd, int Msg, int wParam, ref COPYDATASTRUCT lParam); </code></pre> <p>The handle (<code>hWnd</code>) is not the problem, as this works:</p> <pre><code>int ftprush = FindWindow("TfmRush", null); ShowWindow(ftprush, 8); </code></pre> <p>Which (I didn't paste the dllimport as it's not important here. Let me know if you wish to see it) brings the window to front. Also, I checked by debugging <code>rush_cmdline.exe</code>. So the handle is the same.</p> <p>Two attempts which both fail (silently):</p> <pre><code>public const Int32 WM_COPYDATA = 0x4A; string msg = "RushApp.FTP.Login('backup','',0); "; // 1 byte[] array = Encoding.UTF8.GetBytes((string)msg); int size = Marshal.SizeOf(array[0]) * array.Length + Marshal.SizeOf(array[0]); IntPtr ptr = Marshal.AllocHGlobal(size); Marshal.Copy(array, 0, ptr, array.Length); Marshal.WriteByte(ptr, size - 1, 0); SendMessage(ftprush, WM_COPYDATA, 0, ptr); // 2 public struct COPYDATASTRUCT { public IntPtr dwData; public int cbData; [MarshalAs(UnmanagedType.LPStr)] public string lpData; } COPYDATASTRUCT cds; cds.dwData = (IntPtr)100; cds.lpData = msg; cds.cbData = sarr.Length + 1; SendMessage(ftprush, WM_COPYDATA, 0, ref cds); </code></pre> <p>I would expect at least the 2nd solution to work, as it matches up pretty well with this: <a href="http://www.perlmonks.org/index.pl?node_id=668761" rel="nofollow">perl example</a></p> <p>Any enlightenment is GREATLY appreciated!</p> <p>Thanks,</p> <ul> <li>Frank</li> </ul> <p>UPDATE:</p> <pre><code>string msg = "RushApp.FTP.Login('backup','',0);\0"; var cds = new COPYDATASTRUCT { dwData = new IntPtr(3), cbData = msg.Length + 1, lpData = msg }; IntPtr ftprush = FindWindow("TfmRush", null); SendMessage(ftprush, WM_COPYDATA, IntPtr.Zero, ref cds); </code></pre>

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