在屏幕上的任何地方检测到焦点突出的文本框

Question

I am writing a simple app in C#. I want this app in systray detecting a focused element anywhere on Windows. If the focused element is a textbox (anywhere where it is possible for the user to input text), then the app should display a notification on systray. My problem is, how to detect a focused element and check it?

Answer 1

There is no absolute way of doing that, there are too many controls allow you to add text.

you may search of the caret position like I did in my application, but it is not working every where,

Here is the code I used,

        GUITHREADINFO lpgui = new GUITHREADINFO();
        IntPtr fore = GetForegroundWindow();
        uint tpid = GetWindowThreadProcessId(fore, IntPtr.Zero);
        lpgui.cbSize = Marshal.SizeOf(lpgui.GetType());
        bool flag = GetGUIThreadInfo(tpid, out lpgui);
        WINDOWINFO pwi = new WINDOWINFO();
        pwi.cbSize = (uint)Marshal.SizeOf(pwi.GetType());
        GetWindowInfo((IntPtr)lpgui.hwndCaret, ref pwi);

        if (flag)
        {
            if (!(lpgui.rcCaret.Location.X == 0 && lpgui.rcCaret.Location.Y == 0))
            {

//TODO

            }
        }

this way works fine in too many applications, and you can place this code in a timer or what ever you wish

You have to use winapi, Please inform me if you are not familiar with api

Answer 2

You can use this code to check focused TextBox.

foreach (Control item in this.Controls)
        {
            if (item is TextBox && item.Focused)
            {
                //Write your notification code here.
            }
        }