[DllImport("User32.dll", EntryPoint = "FindWindow")]
        public static extern int FindWindow(string lpClassName,string lpWindowName);
        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);
        [DllImport("user32.dll", EntryPoint = "EnumDesktopWindows", ExactSpelling = false, CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool EnumDesktopWindows(IntPtr hDesktop, EnumDesktopWindowsDelegate lpEnumCallbackFunction, IntPtr lParam);
        public delegate bool EnumDesktopWindowsDelegate(IntPtr hWnd, uint lParam);

新版的framework不知道是否集成 framework提供的类库封装了大多数的API 但有些还是需要使用[DllImport("user32.dll")]
 来自己操作的
如果嫌麻烦呢 就自己封装好 调起来方便

自己封装还不会啊   我手头没书
写代码 清一色开百度

把所有你可能用上的windows api放到一个类中，以后使用时直接通过类名调用