Finding multiple windows with the same title

Question

I am starting an executable several times like this

Process proc = new Process();
proc.StartInfo.FileName = path + "/BuiltGame.exe";
proc.Start();

Process proc1 = new Process();
proc1.StartInfo.FileName = path + "/BuiltGame.exe";
proc1.Start();

Now I want to resize and move the spawned windows.

I am currently using MoveWindow and FindWindow

[DllImport("user32.dll", SetLastError = true)]
internal static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);
[DllImport("user32.dll", SetLastError = true)]
internal static extern IntPtr FindWindow(string windowClass, string title);

Initially I thought that I could just use the handle from the spawned process

 MoveWindow(proc.Handle, 0, 0, 100, 100, true);

But it didn't work and I tried to use FindWindow

IntPtr Handle = FindWindow(null,"MyWindowTitle")

Which indeed worked and the returned handle from FindWindow is a different one that from Process.Handle

After that I tried to use

 MoveWindow(proc.MainWindowHandle, 0, 0, 100, 100, true);

But MainWindowHandle is just 0.

The problem that I now have is that I want to start multiple processes and get the correct window handle from each window but FindWindow only returns the first one.

How would I do this?

Have you tried `EnumWindows`? The accepted answer [here](http://stackoverflow.com/questions/19867402/how-can-i-use-enumwindows-to-find-windows-with-a-specific-caption-title) show how to call it from C#. — Jack Hughes, Jul 17 '15 at 09:43

David Heffernan · Accepted Answer · 2015-07-18T04:19:09.557

3

Call EnumWindows to enumerate top-level windows. For each such window, call GetWindowText to find out its text which you can then compare against your target value.

If you are looking for windows in a specific process, use GetWindowThreadProcessId.

edited Jul 18 '15 at 04:19

answered Jul 17 '15 at 09:42

David Heffernan

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Actually the OP probably wants to use `GetWindowThreadProcessId` to compare against the target process, since the window titles will all be the same. – Jonathan Potter Jul 17 '15 at 21:54
@Jonathan That depends. Yes if you want to find a window from a specific process. But perhaps you want to find all such windows. – David Heffernan Jul 18 '15 at 01:45
*"The problem that I now have is that I want to start multiple processes and get the correct window handle from each window but FindWindow only returns the first one"* suggests he wants to match windows to processes. – Jonathan Potter Jul 18 '15 at 03:13

score 0 · Answer 2 · answered Jul 16 '20 at 17:57

I used this when launching multiple windows for a game, but I'm also waiting a few seconds for it to start up and show a window. If you're getting the MainWindowHandle before the window has a chance to initialize, then this may be some of the issue. This lets me set each position as I'm cycling through processes to launch, before I continue to the next

            // Launch each process
            using (Process myProcess = new Process())
            {
                myProcess.StartInfo.FileName = Folder + "\\executable.exe";
                myProcess.StartInfo.WorkingDirectory = Folder;
                myProcess.StartInfo.UseShellExecute = false;
                myProcess.StartInfo.RedirectStandardInput = true;
                
                myProcess.Start();

                // Wait for process to start up, default 2000ms set elsewhere
                await Task.Delay(LaunchDelayTime);

                // If found, position it.
                if (myProcess.MainWindowHandle != IntPtr.Zero)
                {
                    // Move to WindowLeft x WindowTop, set elsewhere
                    SetWindowPos(myProcess.MainWindowHandle, IntPtr.Zero, (int)WindowLeft, (int)WindowTop, 0, 0, SWP_NOSIZE | SWP_NOZORDER);
                }
            }

Finding multiple windows with the same title

2 Answers2