Question

我在一个进程上创建了一个钩子，以便在Window移动时进行注册。我使用事件常量EVENT_OBJECT_LOCATIONCHANGE，每MSDN

对象已更改位置，形状或大小。系统为以下用户界面元素发送此事件：插入符号和窗口对象。服务器应用程序为其可访问对象发送此事件。

它可以工作，但它也会在应用程序的简单鼠标上触发。任何人都可以解释原因吗？

以下是重现它的示例：

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    static class NativeMethods
    {
        [DllImport("user32.dll")]
        public static extern System.IntPtr SetWinEventHook(uint eventMin, uint eventMax, System.IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

        public delegate void WinEventDelegate(System.IntPtr hWinEventHook, uint eventType, System.IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
    }

    public partial class Form1 : Form
    {
        private const uint WINEVENT_OUTOFCONTEXT = 0x0000;
        private const uint EVENT_OBJECT_LOCATIONCHANGE = 0x800B;

        public Form1()
        {
            InitializeComponent();
            int processId = Process.GetCurrentProcess().Id;

            NativeMethods.SetWinEventHook(EVENT_OBJECT_LOCATIONCHANGE, EVENT_OBJECT_LOCATIONCHANGE, System.IntPtr.Zero, WinEventProc, (uint)processId, (uint)0, WINEVENT_OUTOFCONTEXT);
        }

        private void WinEventProc(System.IntPtr hWinEventHook, uint eventType, System.IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
        {
           if (hwnd == IntPtr.Zero)
            {
                Debug.WriteLine("Mouse moved");
            }
            else
            {
                Debug.WriteLine("Location changed");
            }
        }
    }
}

Answer 1

头文件WinUser.h关于EVENT_OBJECT_LOCATIONCHANGE这样说：

 * Note also that USER will generate LOCATIONCHANGE notifications for two
 * non-window sys objects:
 *      (1) System caret
 *      (2) Cursor

这说明了为什么光标移动时会触发事件。

就像汉斯在评论中说的那样，只需用OBJID_CURSOR过滤对象ID。

为什么SetWinEventHook与EVENT_OBJECT_LOCATIONCHANGE触发鼠标移动？

1 个答案: