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  4. How can I get handle (IntPtr) to a "sub"-form in another application?

How can I get handle (IntPtr) to a "sub"-form in another application?

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  • A arnold_w

    I would like to show a WinForms MessageBox centered on top of another application's (TortoiseGit) "sub"-form, i.e. a form (the TortoiseGit checkout form) on top of the main form (the TortoiseGit log window). I am able to successfully find the process (TortoiseGitProc) and from there I can successfully get a MainWindowHandle to the main form, but how do get from there to the "sub"-form (the TortoiseGit checkout form)?

    Richard Andrew x64R Offline
    Richard Andrew x64R Offline
    Richard Andrew x64
    wrote on last edited by
    #11

    See if this SO answer helps: c# - How to enumerate all windows belonging to a particular process using .NET? - Stack Overflow[^] (Particularly the second answer.)

    The difficult we do right away... ...the impossible takes slightly longer.

    A 1 Reply Last reply
    0
    • Richard Andrew x64R Richard Andrew x64

      This is kind of a side point, but I see that your CheckWindow function will return true in any circumstance.

      The difficult we do right away... ...the impossible takes slightly longer.

      A Offline
      A Offline
      arnold_w
      wrote on last edited by
      #12

      Yes, I added the line

      return true; // My modified code to check all windows

      on purpose because I wanted to log all window texts. My goals was to find the particular window that has the window text "C:\DummyRepo - Switch/Checkout - TortoiseGit", but all I found was windows having window texts such as "Form1", "MSCTFIME UI" and "Default IME".

      1 Reply Last reply
      0
      • Richard Andrew x64R Richard Andrew x64

        See if this SO answer helps: c# - How to enumerate all windows belonging to a particular process using .NET? - Stack Overflow[^] (Particularly the second answer.)

        The difficult we do right away... ...the impossible takes slightly longer.

        A Offline
        A Offline
        arnold_w
        wrote on last edited by
        #13

        That's pretty much what I already do, I am able to get a bunch of windows but I can't tell which one corresponds to

        Window 000C0678 "C:\DummyRepo - Switch/Checkout - TortoiseGit" #32770 (Dialog)

        because I can't find any window that has the heading "C:\DummyRepo - Switch/Checkout - TortoiseGit" using GetWindowText. Now, on the other hand, the pure C# (no win32 pinvoke involved) property Process.MainWindowTitle seems to return the proper string, but I can only apply it to the de facto main window ("C:\DummyRepo - Log Messages - TortoiseGit"), not to the "secondary sibling"-window ("C:\DummyRepo - Switch/Checkout - TortoiseGit").

        Richard Andrew x64R 1 Reply Last reply
        0
        • A arnold_w

          That's pretty much what I already do, I am able to get a bunch of windows but I can't tell which one corresponds to

          Window 000C0678 "C:\DummyRepo - Switch/Checkout - TortoiseGit" #32770 (Dialog)

          because I can't find any window that has the heading "C:\DummyRepo - Switch/Checkout - TortoiseGit" using GetWindowText. Now, on the other hand, the pure C# (no win32 pinvoke involved) property Process.MainWindowTitle seems to return the proper string, but I can only apply it to the de facto main window ("C:\DummyRepo - Log Messages - TortoiseGit"), not to the "secondary sibling"-window ("C:\DummyRepo - Switch/Checkout - TortoiseGit").

          Richard Andrew x64R Offline
          Richard Andrew x64R Offline
          Richard Andrew x64
          wrote on last edited by
          #14

          That's not what you're already doing. You must be looking at the first answer to the question. Look at the SECOND answer to the question on that page. The second answer uses the function EnumThreadWindows.

          The difficult we do right away... ...the impossible takes slightly longer.

          A 1 Reply Last reply
          0
          • Richard Andrew x64R Richard Andrew x64

            That's not what you're already doing. You must be looking at the first answer to the question. Look at the SECOND answer to the question on that page. The second answer uses the function EnumThreadWindows.

            The difficult we do right away... ...the impossible takes slightly longer.

            A Offline
            A Offline
            arnold_w
            wrote on last edited by
            #15

            Ahhh, you mean this:

            const uint WM_GETTEXT = 0x000D;
            StringBuilder message = new StringBuilder(1000);
            SendMessage(handle, WM_GETTEXT, message.Capacity, message);

            Yes, that works great!!! Thank you! This is the complete code:

            public partial class Form1 : Form
            {
            public Form1()
            {
            InitializeComponent();
            WindowWrapper parentForm = ProcessWindowsHelper.getHandleToAnotherProcessWindow("TortoiseGitProc", "Switch/Checkout");
            MessageBoxEx.Show(parentForm, "Hello on top of TortoiseGit Switch/Checkout dialog");
            }
            }
            public class ProcessWindowsHelper
            {
            private delegate bool EnumThreadWndProc(IntPtr hWnd, IntPtr lp);
            [DllImport("user32.dll")]
            private static extern bool EnumThreadWindows(int tid, EnumThreadWndProc callback, IntPtr lp);
            [DllImport("user32.dll", CharSet = CharSet.Auto)]
            static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);
            delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);

            private const uint WM\_GETTEXT = 0x000D;
            
            public static WindowWrapper getHandleToAnotherProcessWindow(string processName, string substringInAnotherProcessWindow)
            {
                Process myProcess = findProcessByName(processName);
                IEnumerable allHandlesInMyProcess = EnumerateProcessWindowHandles(myProcess.Id);
                foreach (IntPtr handle in allHandlesInMyProcess)
                {
                    StringBuilder message = new StringBuilder(1000);
                    SendMessage(handle, WM\_GETTEXT, message.Capacity, message);
                    if (message.ToString().Contains(substringInAnotherProcessWindow))
                    {
                        Debug.WriteLine(message);
                        return new WindowWrapper(handle);
                    }
                }
                return null;
            }
            
            private static IEnumerable EnumerateProcessWindowHandles(int processId)
            {
                List handles = new List();
                ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                for (int i = 0; i < processThreadCollection.Count; i++)
                {
                    ProcessThread thread;
                    thread = processThreadCollection\[i\];
                    EnumThreadWindows(thread.Id, 
                        delegate(IntPtr hWnd, IntPtr lParam)
                        {
                            handles.Add(hWnd);
                            return true;
                        }, 
                        IntPtr.Zero);
                }
                return handles;
            }
            
            private static Process find
            
            Richard Andrew x64R A 2 Replies Last reply
            0
            • A arnold_w

              Ahhh, you mean this:

              const uint WM_GETTEXT = 0x000D;
              StringBuilder message = new StringBuilder(1000);
              SendMessage(handle, WM_GETTEXT, message.Capacity, message);

              Yes, that works great!!! Thank you! This is the complete code:

              public partial class Form1 : Form
              {
              public Form1()
              {
              InitializeComponent();
              WindowWrapper parentForm = ProcessWindowsHelper.getHandleToAnotherProcessWindow("TortoiseGitProc", "Switch/Checkout");
              MessageBoxEx.Show(parentForm, "Hello on top of TortoiseGit Switch/Checkout dialog");
              }
              }
              public class ProcessWindowsHelper
              {
              private delegate bool EnumThreadWndProc(IntPtr hWnd, IntPtr lp);
              [DllImport("user32.dll")]
              private static extern bool EnumThreadWindows(int tid, EnumThreadWndProc callback, IntPtr lp);
              [DllImport("user32.dll", CharSet = CharSet.Auto)]
              static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);
              delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);

              private const uint WM\_GETTEXT = 0x000D;
              
              public static WindowWrapper getHandleToAnotherProcessWindow(string processName, string substringInAnotherProcessWindow)
              {
                  Process myProcess = findProcessByName(processName);
                  IEnumerable allHandlesInMyProcess = EnumerateProcessWindowHandles(myProcess.Id);
                  foreach (IntPtr handle in allHandlesInMyProcess)
                  {
                      StringBuilder message = new StringBuilder(1000);
                      SendMessage(handle, WM\_GETTEXT, message.Capacity, message);
                      if (message.ToString().Contains(substringInAnotherProcessWindow))
                      {
                          Debug.WriteLine(message);
                          return new WindowWrapper(handle);
                      }
                  }
                  return null;
              }
              
              private static IEnumerable EnumerateProcessWindowHandles(int processId)
              {
                  List handles = new List();
                  ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                  for (int i = 0; i < processThreadCollection.Count; i++)
                  {
                      ProcessThread thread;
                      thread = processThreadCollection\[i\];
                      EnumThreadWindows(thread.Id, 
                          delegate(IntPtr hWnd, IntPtr lParam)
                          {
                              handles.Add(hWnd);
                              return true;
                          }, 
                          IntPtr.Zero);
                  }
                  return handles;
              }
              
              private static Process find
              
              Richard Andrew x64R Offline
              Richard Andrew x64R Offline
              Richard Andrew x64
              wrote on last edited by
              #16

              Glad you got it sorted! 😉

              The difficult we do right away... ...the impossible takes slightly longer.

              1 Reply Last reply
              0
              • A arnold_w

                Ahhh, you mean this:

                const uint WM_GETTEXT = 0x000D;
                StringBuilder message = new StringBuilder(1000);
                SendMessage(handle, WM_GETTEXT, message.Capacity, message);

                Yes, that works great!!! Thank you! This is the complete code:

                public partial class Form1 : Form
                {
                public Form1()
                {
                InitializeComponent();
                WindowWrapper parentForm = ProcessWindowsHelper.getHandleToAnotherProcessWindow("TortoiseGitProc", "Switch/Checkout");
                MessageBoxEx.Show(parentForm, "Hello on top of TortoiseGit Switch/Checkout dialog");
                }
                }
                public class ProcessWindowsHelper
                {
                private delegate bool EnumThreadWndProc(IntPtr hWnd, IntPtr lp);
                [DllImport("user32.dll")]
                private static extern bool EnumThreadWindows(int tid, EnumThreadWndProc callback, IntPtr lp);
                [DllImport("user32.dll", CharSet = CharSet.Auto)]
                static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);
                delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);

                private const uint WM\_GETTEXT = 0x000D;
                
                public static WindowWrapper getHandleToAnotherProcessWindow(string processName, string substringInAnotherProcessWindow)
                {
                    Process myProcess = findProcessByName(processName);
                    IEnumerable allHandlesInMyProcess = EnumerateProcessWindowHandles(myProcess.Id);
                    foreach (IntPtr handle in allHandlesInMyProcess)
                    {
                        StringBuilder message = new StringBuilder(1000);
                        SendMessage(handle, WM\_GETTEXT, message.Capacity, message);
                        if (message.ToString().Contains(substringInAnotherProcessWindow))
                        {
                            Debug.WriteLine(message);
                            return new WindowWrapper(handle);
                        }
                    }
                    return null;
                }
                
                private static IEnumerable EnumerateProcessWindowHandles(int processId)
                {
                    List handles = new List();
                    ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                    for (int i = 0; i < processThreadCollection.Count; i++)
                    {
                        ProcessThread thread;
                        thread = processThreadCollection\[i\];
                        EnumThreadWindows(thread.Id, 
                            delegate(IntPtr hWnd, IntPtr lParam)
                            {
                                handles.Add(hWnd);
                                return true;
                            }, 
                            IntPtr.Zero);
                    }
                    return handles;
                }
                
                private static Process find
                
                A Offline
                A Offline
                arnold_w
                wrote on last edited by
                #17

                Well, I guess no joy lasts forever... In case somebody is using bash.exe instead of TortoiseGit to Switch/Checkout, then I wanted to do the same thing with bash.exe as the parent form. But when I call

                parentForm = ProcessWindowsHelper.getHandleToAnotherProcessWindow("bash", "MING")

                then it seems the handles list inside the EnumerateProcessWindowHandles method doesn't get any elements.

                private static IEnumerable EnumerateProcessWindowHandles(int processId)
                {
                    List handles = new List();
                    ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                    for (int i = 0; i < processThreadCollection.Count; i++)
                    {
                        ProcessThread thread;
                        thread = processThreadCollection\[i\];
                        EnumThreadWindows(thread.Id, 
                            delegate(IntPtr hWnd, IntPtr lParam)
                            {
                                handles.Add(hWnd);
                                return true;
                            }, 
                            IntPtr.Zero);
                    }
                    return handles;
                }
                

                The call to Process.GetProcessById(processId).Threads returns 3 threads, but nothing gets added to the handles list. Does anybody know why? When I look at the information in Spy++ I see the following:

                Window OOOA9B72 "MINGW64:/c/dummyRepo" mintty

                Windows Properties, General tab:

                Window Caption: MINGW64:/c/dummyRepo
                Window Handle: OOOA9B72
                Window Proc: (Unavailable)(Unicode)
                Rectangle: (86, 89)-(681, 466), 595x377
                Restored Rect: (86, 89)-(681, 466), 595x377
                Client Rect: (8, 31)-(570, 369), 562x338
                Instance Handle 00400000
                Menu Handle 00000000
                User Data 00000000
                Windows Bytes:

                Richard Andrew x64R 1 Reply Last reply
                0
                • A arnold_w

                  Well, I guess no joy lasts forever... In case somebody is using bash.exe instead of TortoiseGit to Switch/Checkout, then I wanted to do the same thing with bash.exe as the parent form. But when I call

                  parentForm = ProcessWindowsHelper.getHandleToAnotherProcessWindow("bash", "MING")

                  then it seems the handles list inside the EnumerateProcessWindowHandles method doesn't get any elements.

                  private static IEnumerable EnumerateProcessWindowHandles(int processId)
                  {
                      List handles = new List();
                      ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                      for (int i = 0; i < processThreadCollection.Count; i++)
                      {
                          ProcessThread thread;
                          thread = processThreadCollection\[i\];
                          EnumThreadWindows(thread.Id, 
                              delegate(IntPtr hWnd, IntPtr lParam)
                              {
                                  handles.Add(hWnd);
                                  return true;
                              }, 
                              IntPtr.Zero);
                      }
                      return handles;
                  }
                  

                  The call to Process.GetProcessById(processId).Threads returns 3 threads, but nothing gets added to the handles list. Does anybody know why? When I look at the information in Spy++ I see the following:

                  Window OOOA9B72 "MINGW64:/c/dummyRepo" mintty

                  Windows Properties, General tab:

                  Window Caption: MINGW64:/c/dummyRepo
                  Window Handle: OOOA9B72
                  Window Proc: (Unavailable)(Unicode)
                  Rectangle: (86, 89)-(681, 466), 595x377
                  Restored Rect: (86, 89)-(681, 466), 595x377
                  Client Rect: (8, 31)-(570, 369), 562x338
                  Instance Handle 00400000
                  Menu Handle 00000000
                  User Data 00000000
                  Windows Bytes:

                  Richard Andrew x64R Offline
                  Richard Andrew x64R Offline
                  Richard Andrew x64
                  wrote on last edited by
                  #18

                  Have you stepped through it in the debugger? Does it find the correct process? Which line of code is failing?

                  The difficult we do right away... ...the impossible takes slightly longer.

                  A 1 Reply Last reply
                  0
                  • Richard Andrew x64R Richard Andrew x64

                    Have you stepped through it in the debugger? Does it find the correct process? Which line of code is failing?

                    The difficult we do right away... ...the impossible takes slightly longer.

                    A Offline
                    A Offline
                    arnold_w
                    wrote on last edited by
                    #19

                    Yes, I stepped it. I first rewrote the method EnumerateProcessWindowHandles according to this:

                    private static List handles;

                    private static IEnumerable EnumerateProcessWindowHandles(int processId)
                    {
                    handles = new List();
                    ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                    for (int i = 0; i < processThreadCollection.Count; i++)
                    {
                    ProcessThread thread; // If I put a breakpoint here, the debugger stops 3 times
                    thread = processThreadCollection[i];
                    EnumThreadWindows(thread.Id, myDelegate, IntPtr.Zero);
                    }
                    return handles;
                    }

                    private static bool myDelegate(IntPtr hWnd, IntPtr lParam)
                    {
                    handles.Add(hWnd); // If I put a breakpoint here, then the debugger never stops
                    return true;
                    }

                    So, something seems to go wrong inside the call to EnumThreadWindows, but that's a Win32 function and I don't know how to put a breakpoint inside it or how to step through it.

                    Richard Andrew x64R 1 Reply Last reply
                    0
                    • A arnold_w

                      Yes, I stepped it. I first rewrote the method EnumerateProcessWindowHandles according to this:

                      private static List handles;

                      private static IEnumerable EnumerateProcessWindowHandles(int processId)
                      {
                      handles = new List();
                      ProcessThreadCollection processThreadCollection = Process.GetProcessById(processId).Threads;
                      for (int i = 0; i < processThreadCollection.Count; i++)
                      {
                      ProcessThread thread; // If I put a breakpoint here, the debugger stops 3 times
                      thread = processThreadCollection[i];
                      EnumThreadWindows(thread.Id, myDelegate, IntPtr.Zero);
                      }
                      return handles;
                      }

                      private static bool myDelegate(IntPtr hWnd, IntPtr lParam)
                      {
                      handles.Add(hWnd); // If I put a breakpoint here, then the debugger never stops
                      return true;
                      }

                      So, something seems to go wrong inside the call to EnumThreadWindows, but that's a Win32 function and I don't know how to put a breakpoint inside it or how to step through it.

                      Richard Andrew x64R Offline
                      Richard Andrew x64R Offline
                      Richard Andrew x64
                      wrote on last edited by
                      #20

                      You need to put a breakpoint inside the "myDelegate" callback to see if ANY windows are being found, not just ones that match your substring. But first, verify that it is indeed finding the correct process. Compare the ProcessId to the one shown by Task Manager. EDIT: I'm sorry I didn't see that you had already tried the breakpoint inside the callback. The only thing I can think of at this moment is to make sure it is finding the correct process.

                      The difficult we do right away... ...the impossible takes slightly longer.

                      A 1 Reply Last reply
                      0
                      • Richard Andrew x64R Richard Andrew x64

                        You need to put a breakpoint inside the "myDelegate" callback to see if ANY windows are being found, not just ones that match your substring. But first, verify that it is indeed finding the correct process. Compare the ProcessId to the one shown by Task Manager. EDIT: I'm sorry I didn't see that you had already tried the breakpoint inside the callback. The only thing I can think of at this moment is to make sure it is finding the correct process.

                        The difficult we do right away... ...the impossible takes slightly longer.

                        A Offline
                        A Offline
                        arnold_w
                        wrote on last edited by
                        #21

                        It is finding the right bash.exe process (there is only 1 running) and it successfully finds its 3 threads. As you said, the filtering with the substrings happens later and by then there are no handles at all to filter.

                        Richard Andrew x64R 1 Reply Last reply
                        0
                        • A arnold_w

                          It is finding the right bash.exe process (there is only 1 running) and it successfully finds its 3 threads. As you said, the filtering with the substrings happens later and by then there are no handles at all to filter.

                          Richard Andrew x64R Offline
                          Richard Andrew x64R Offline
                          Richard Andrew x64
                          wrote on last edited by
                          #22

                          I have one last thing. I'm not familiar with bash, is it a command line program?

                          The difficult we do right away... ...the impossible takes slightly longer.

                          A 1 Reply Last reply
                          0
                          • Richard Andrew x64R Richard Andrew x64

                            I have one last thing. I'm not familiar with bash, is it a command line program?

                            The difficult we do right away... ...the impossible takes slightly longer.

                            A Offline
                            A Offline
                            arnold_w
                            wrote on last edited by
                            #23

                            Yes, I think it's some kind of command prompt that is standard for Unix systems, but it exists for Windows also. I've seen some of my colleagues (those that prefer typing over interacting with GUI:s) type

                            $ git.exe checkout develop

                            when they want to checkout in Git.

                            Richard Andrew x64R 1 Reply Last reply
                            0
                            • A arnold_w

                              Yes, I think it's some kind of command prompt that is standard for Unix systems, but it exists for Windows also. I've seen some of my colleagues (those that prefer typing over interacting with GUI:s) type

                              $ git.exe checkout develop

                              when they want to checkout in Git.

                              Richard Andrew x64R Offline
                              Richard Andrew x64R Offline
                              Richard Andrew x64
                              wrote on last edited by
                              #24

                              Bingo! That must be why you're not finding any Windows. I can think of two possibilities at this point. 1. It might be that you need to find bash's parent process and enumerate the windows of that process instead. 2. It might be that the Linux Subsystem is interfering somehow.

                              The difficult we do right away... ...the impossible takes slightly longer.

                              A 1 Reply Last reply
                              0
                              • Richard Andrew x64R Richard Andrew x64

                                Bingo! That must be why you're not finding any Windows. I can think of two possibilities at this point. 1. It might be that you need to find bash's parent process and enumerate the windows of that process instead. 2. It might be that the Linux Subsystem is interfering somehow.

                                The difficult we do right away... ...the impossible takes slightly longer.

                                A Offline
                                A Offline
                                arnold_w
                                wrote on last edited by
                                #25

                                When I closed my bash.exe command prompt, I could see that the following processes disappeared: backgroundTaskHost, bash, conhost, git-bash, mintty and RuntimeBroker. When I tried mintty instead of bash, then it worked great! Again, thanks for your help!

                                Richard Andrew x64R 1 Reply Last reply
                                0
                                • A arnold_w

                                  When I closed my bash.exe command prompt, I could see that the following processes disappeared: backgroundTaskHost, bash, conhost, git-bash, mintty and RuntimeBroker. When I tried mintty instead of bash, then it worked great! Again, thanks for your help!

                                  Richard Andrew x64R Offline
                                  Richard Andrew x64R Offline
                                  Richard Andrew x64
                                  wrote on last edited by
                                  #26

                                  Happy to help! :)

                                  The difficult we do right away... ...the impossible takes slightly longer.

                                  1 Reply Last reply
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