检测使用C＃更改的活动窗口而不进行轮询

创建一个新的Windows窗体项目，添加一个文本框，使其多行，并将文本框的Dock属性设置为fill，将其命名为Log并粘贴以下代码（您需要将System.Runtime.InteropServices添加到您的用法中）。
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    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() + "rn";    }