WPF窗体不获取输入焦点（开发屏幕键盘必备）

       [DllImport("user32.dll")]
        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern UInt32 GetWindowLong(IntPtr hWnd, int nIndex);

 

 

private void mainwindows_Loaded(object sender, RoutedEventArgs e)
        {
            //以下代码不能放到构造函数里，否则窗体丙柄为0
            WindowInteropHelper wndHelper = new WindowInteropHelper(this);

            IntPtr HWND = wndHelper.Handle;
            int GWL_EXSTYLE = -20;
           
            //GetWindowLong(HWND, GWL_EXSTYLE);
          
            SetWindowLong(HWND, GWL_EXSTYLE, (IntPtr)(0x8000000)); //让当前窗体不获取输入焦点
        }