c# - 使用 C# 检测事件窗口更改而不轮询

Question

当当前事件窗口发生变化时，如何调用回调。我已经看到如何使用 CBTProc 完成它。但是，全局事件不容易与托管代码 Hook 。我有兴趣找到一种不需要轮询的方法。我更喜欢事件驱动的方法。

问候

Answer 1

创建一个新的窗体项目，添加一个文本框，使其成为多行，并将文本框的 Dock 属性设置为填充，将其命名为 Log 并粘贴以下代码(您需要将 System.Runtime.InteropServices 添加到您的使用)...

    WinEventDelegate dele = null;

    public Form1()
    {
        InitializeComponent();
        dele = new WinEventDelegate(WinEventProc);
        IntPtr m_hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, dele, 0, 0, WINEVENT_OUTOFCONTEXT);
    }

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

    [DllImport("user32.dll")]
    static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

    private const uint WINEVENT_OUTOFCONTEXT = 0;
    private const uint EVENT_SYSTEM_FOREGROUND = 3;

    [DllImport("user32.dll")]
    static extern IntPtr GetForegroundWindow();

    [DllImport("user32.dll")]
    static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);

    private string GetActiveWindowTitle()
    {
        const int nChars = 256;
        IntPtr handle = IntPtr.Zero;
        StringBuilder Buff = new StringBuilder(nChars);
        handle = GetForegroundWindow();

        if (GetWindowText(handle, Buff, nChars) > 0)
        {
            return Buff.ToString();
        }
        return null;
    }

    public void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
    {
        Log.Text += GetActiveWindowTitle() + "\r\n";
    }