C#用API如何遍历所有窗口句柄

1.首先需要声明一个委托函数用于 Win32 API - EnumWindows 的回调函数：

private delegate bool WNDENUMPROC(IntPtr hWnd, int lParam); //IntPtr hWnd用int也可以

2.然后利用 C# 中的平台调用声明从 USER32.DLL 库中调用 API - EnumWindows，具体参数请参考 MSDN - Win32 API。

[DllImport("user32.dll")]

private static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, int lParam);

3.最后实例化委托，调用 EnumWindows。

EnumWindows(delegate(IntPtr hWnd, int lParam) {……},0);

private delegate bool WNDENUMPROC(IntPtr hWnd, int lParam);

//用来遍历所有窗口 
       [DllImport("user32.dll")] 
        private static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, int lParam);

//获取窗口Text 
        [DllImport("user32.dll")] 
        private static extern int GetWindowTextW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);

//获取窗口类名 
        [DllImport("user32.dll")] 
        private static extern int GetClassNameW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount); 

//自定义一个类，用来保存句柄信息，在遍历的时候，随便也用空上句柄来获取些信息，呵呵 
        public struct WindowInfo         

        { 
            public IntPtr hWnd; 
            public string szWindowName; 
            public string szClassName; 
        }

        public WindowInfo[] GetAllDesktopWindows() 
        { 

//用来保存窗口对象 列表
            List<WindowInfo> wndList = new List<WindowInfo>();

            //enum all desktop windows 
            EnumWindows(delegate(IntPtr hWnd, int lParam) 
            { 
                WindowInfo wnd = new WindowInfo(); 
                StringBuilder sb = new StringBuilder(256);

                //get hwnd 
                wnd.hWnd = hWnd;

                //get window name  
                GetWindowTextW(hWnd, sb, sb.Capacity); 
                wnd.szWindowName = sb.ToString();

                //get window class 
                GetClassNameW(hWnd, sb, sb.Capacity); 
                wnd.szClassName = sb.ToString();

                //add it into list 
                wndList.Add(wnd); 
                return true; 
            }, 0);

            return wndList.ToArray(); 
        }