Question

How can we get the handle of a window that doesn’t have a title? Is there a way to enumerate all the windows on desktop and filter the window that don’t have a title (in my case, there is only one) and getting the handle of it.. or by specifying other attributes like a window that has a specific button or listbox etc…

Answer 1

This should do it:

    ...
    using System.Runtime.InteropServices;
    using System.Diagnostics;

    ...

public class foo()
{
    ...

    [DllImport ("user32")]
    internal static extern int GetWindowText (int hWnd, String text, int nMaxCount);

    [DllImport ("user32.dll")]
    public static extern int GetWindowTextLength (int hWnd);

    [DllImport ("user32.dll")]
    public static extern int FindWindow (String text, String class_name);

    [DllImport ("user32.dll")]
    public static extern int FindWindowEx (int parent, int start, String class_name);

    [DllImport ("user32.dll")]
    public static extern int GetWindow (int parent, uint cmd);

    public List<int> FindTitlelessWindows()
    {
        List<int> titleless = new List<int> ();

        Process [] procs = Process.GetProcesses ();
        IntPtr hWnd;

        foreach (Process proc in procs)
        {
            hWnd = proc.MainWindowHandle;
            if (hWnd != IntPtr.Zero)
            {
                TraverseHierarchy (hWnd.ToInt32 (), 0, titleless);

            }
        }

        foreach (int i in titleless)
        {
            System.Console.WriteLine (i);
        }

        return titleless;
    }

    public void TraverseHierarchy (int parent, int child, List<int> titleless)
    {
        String text = "";
        GetWindowText (parent, text, GetWindowTextLength (parent));
        if (String.IsNullOrEmpty (text))
        {
            titleless.Add (parent);
        }

        TraverseChildern (parent, titleless);
        TraversePeers (parent, child, titleless);

    }

    public void TraverseChildern(int handle, List<int> titleless)
    {
        // First traverse child windows
        const uint GW_CHILD = 0x05;
        int child = GetWindow (handle, GW_CHILD);
        if (0 != child)
        {
            TraverseHierarchy (child, 0, titleless);

        }
    }

    public void TraversePeers(int parent, int start, List<int> titleless)
    {
        // Next traverse peers
        int peer = FindWindowEx(parent, start, "");
        if (0 != peer)
        {
            TraverseHierarchy (parent, peer, titleless);
        }

    }
}