如何使用C＃捕获窗口焦点更改事件

Question

I want to build an application to monitor all running windows focus change event. I know WM_KILLFOCUS (0x0008) and WM_SETFOCUS(0x0007) and when window lost focus or get focus, the message will be sent. with help of spy++, I get output like this:

<00001> 0005069A S WM_SETFOCUS hwndLoseFocus:(null)

<00002> 0005069A R WM_SETFOCUS

<00003> 0005069A S WM_KILLFOCUS hwndGetFocus:(null)

<00004> 0005069A R WM_KILLFOCUS

<00005> 00010096 S WM_SETFOCUS hwndLoseFocus:(null)

<00006> 00010096 R WM_SETFOCUS

I tried to write following c# code to make it work in my winfrom application:

[StructLayout(LayoutKind.Sequential)]
public struct NativeMessage
{
 public IntPtr handle;
 public uint msg;
 public IntPtr wParam;
 public IntPtr lParam;
 public uint time;
 public System.Drawing.Point p;
}
[DllImport("user32.dll")]
public static extern sbyte GetMessage(out NativeMessage lpMsg, IntPtr hWnd, uint wMsgFilterMin, uint wMsgFilterMax);

NativeMessage msg = new NativeMessage();
        sbyte ret;
        while ((ret = GetMessage( out msg, IntPtr.Zero, 0, 0)) != -1)
        {
            if (ret == -1)
            {
                //-1 indicates an error
            }
            else
            {
                if (msg.msg == 0x0008 || msg.msg == 0x0007)
                {
                    this.textBox1.Text = "ret is: " + ret;
                }
            }
        }

Unfortunately, I never get message WM_KILLFOCUS and WM_SETFOCUS.

I actually want to trigger an event in my application when I find the get/lost focus event happens in all running windows. How can I make it work?

Thanks.

Answer 1

使用Form.Actived和Form.Deactivate事件来查找表单是丢失还是获得焦点。

Answer 2

如果您真的想进入本机窗口消息的令人讨厌的世界，则应使用WndProc