C# wpf实现截屏框热键截屏的示例代码

[System.Runtime.InteropServices.DllImport("user32")]
private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint controlKey, uint virtualKey);
[System.Runtime.InteropServices.DllImport("user32")]
private static extern bool UnregisterHotKey(IntPtr hWnd, int id);

 private void Window_SourceInitialized(object sender, EventArgs e)
 {
     //注册alt+d热键,0x44为d,其他虚拟键值请查看：https://learn.microsoft.com/zh-tw/windows/win32/inputdev/virtual-key-codes
     HotKey k = new HotKey(this, HotKey.KeyFlags.MOD_ALT, 0x44);
     k.OnHotKey += K_OnHotKey;
     Visibility = Visibility.Collapsed;
 }

  const int DESKTOPVERTRES = 117;
        const int DESKTOPHORZRES = 118;
        [DllImport("gdi32.dll")]
        static extern int GetDeviceCaps(
   IntPtr hdc, // handle to DC  
   int nIndex // index of capability  
   );
        [DllImport("user32.dll")]
        static extern IntPtr GetDC(IntPtr ptr);
        [DllImport("user32.dll", EntryPoint = "ReleaseDC")]
        static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);
        /// <summary>  
        /// 获取真实设置的桌面分辨率大小  
        /// </summary>  
        static Size DESKTOP
        {
            get
            {
                IntPtr hdc = GetDC(IntPtr.Zero);
                Size size = new Size();
                size.Width = GetDeviceCaps(hdc, DESKTOPHORZRES);
                size.Height = GetDeviceCaps(hdc, DESKTOPVERTRES);
                ReleaseDC(IntPtr.Zero, hdc);
                return size;
            }
        }

//截屏并显示到窗口
void Snapshot()
{
    //获取桌面实际分辨率，可以解决程序运行后修改dpi，截图区域不正常的问题
    var leftTop = new Point(0, 0);
    var rightBottom = new Point(DESKTOP.Width, DESKTOP.Height);
    var bitmap = Snapshot((int)leftTop.X, (int)leftTop.Y, (int)(rightBottom.X - leftTop.X), (int)(rightBottom.Y - leftTop.Y));
    var bmp = BitmapToWriteableBitmap(bitmap);
    bitmap.Dispose();
    //显示到窗口
    grdGlobal.Background = new ImageBrush(bmp);
}

//获取桌面所有窗口
_windows = WindowList.GetAllWindows();
IntPtr hwnd = new WindowInteropHelper(this).Handle;
//去除不可见窗口以及自己
_windows.RemoveAll((ele) => { return !ele.isVisible || ele.Handle == hwnd; });

//窗口是以z顺序排列的查找到第一个匹配的窗口即可
var screenPoint = grdGlobal.PointToScreen(point);
foreach (var window in _windows)
{
    if (window.rect.Contains(screenPoint))
    //获取在鼠标所在区域的窗口
    {
        try
        {
            if (window.rect.Right > window.rect.Left && window.rect.Bottom > window.rect.Top)
            //
            {
                var topLeft = grdGlobal.PointFromScreen(window.rect.TopLeft);
                var bottomRight = grdGlobal.PointFromScreen(window.rect.BottomRight);
                Thickness thickness = new Thickness(topLeft.X, topLeft.Y, grdGlobal.ActualWidth - bottomRight.X, grdGlobal.ActualHeight - bottomRight.Y);
                 //修正边界
                if (thickness.Left < 0) thickness.Left = 0;
                if (thickness.Top < 0) thickness.Top = 0;
                if (thickness.Right < 0) thickness.Right = 0;
                if (thickness.Bottom < 0) thickness.Bottom = 0;
                //将截屏框显示在窗口位置
                leftPanel.Width = thickness.Left;
                topPanel.Height = thickness.Top;
                rightPanel.Width = thickness.Right;
                bottomPanel.Height = thickness.Bottom;
                break;
            }
        }
        catch { }
    }
}

//将截屏框移动到点击位置
leftPanel.Width = p.X;
topPanel.Height = p.Y;
rightPanel.Width = grdGlobal.ActualWidth - p.X;
bottomPanel.Height = grdGlobal.ActualHeight - p.Y;

//手动触发截屏框滑块拖动事件
MouseButtonEventArgs downEvent = new MouseButtonEventArgs(Mouse.PrimaryDevice, Environment.TickCount, MouseButton.Left)
{ RoutedEvent = FrameworkElement.MouseLeftButtonDownEvent };
thumb.RaiseEvent(downEvent);

//滑块需要的偏移量
Point? _thumbOffset;
var thumb = sender as FrameworkElement;
if (!new Rect(0, 0, thumb.ActualWidth, thumb.ActualHeight).Contains(new Point(e.HorizontalOffset, e.VerticalOffset)))
//鼠标起始位置超出了控件范围，则记录中心点偏移在拖动时修正
{
    _thumbOffset = new Point(e.HorizontalOffset - thumb.ActualWidth / 2, e.VerticalOffset - thumb.ActualHeight / 2);
}

var horizontalChange = e.HorizontalChange;
var verticalChange = e.VerticalChange;
if (_thumbOffset != null)
//修正偏移
{
    horizontalChange += _thumbOffset.Value.X;
    verticalChange += _thumbOffset.Value.Y;
}

if (width >= 0)
{
    leftPanel.Width = left >= 0 ? left : 0;
    rightPanel.Width = right >= 0 ? right : 0;
}
else{
//此处将事件转移到反方向的Thumb
}

if (height >= 0)
{
    topPanel.Height = top >= 0 ? top : 0;
    bottomPanel.Height = bottom >= 0 ? bottom : 0;
}
else
{
//此处将事件转移到反方向的Thumb
}

//当前的Thumb触发鼠标弹起事件，结束拖动
MouseButtonEventArgs upEvent = new MouseButtonEventArgs(Mouse.PrimaryDevice, Environment.TickCount, MouseButton.Left)
{ RoutedEvent = FrameworkElement.MouseLeftButtonUpEvent };
thumb.RaiseEvent(upEvent);
//反方向的Thumb触发鼠标按下事件，开始拖动
MouseButtonEventArgs downEvent = new MouseButtonEventArgs(Mouse.PrimaryDevice, Environment.TickCount, MouseButton.Left)
{ RoutedEvent = FrameworkElement.MouseLeftButtonDownEvent };
t.RaiseEvent(downEvent);

if (thumb.HorizontalAlignment == HorizontalAlignment.Left)
//从左到右转移的修正
{
    leftPanel.Width = grdGlobal.ActualWidth - rightPanel.Width;
}
else
//从右到左转移的修正
{
    rightPanel.Width = grdGlobal.ActualWidth - leftPanel.Width;
}

 if (thumb.VerticalAlignment == VerticalAlignment.Top)
 //从上到下转移的修正
 {
     topPanel.Height = grdGlobal.ActualHeight - bottomPanel.Height;
 }
 else
 //从下到上转移的修正
 {
     bottomPanel.Height = grdGlobal.ActualHeight - topPanel.Height;
 }

//获取截屏框的图片
WriteableBitmap GetClipImage()
{
    var bursh = grdGlobal.Background as ImageBrush;
    if (bursh != null)
    {
        //裁剪
        //全屏图片
        var screenWb = bursh.ImageSource as WriteableBitmap;
        //获取截取区域
        var leftTop = clipRect.PointToScreen(new Point(0, 0));
        var rightBottom = clipRect.PointToScreen(new Point(clipRect.ActualWidth, clipRect.ActualHeight));
        var rect = new Int32Rect((int)leftTop.X, (int)leftTop.Y, (int)(rightBottom.X - leftTop.X), (int)(rightBottom.Y - leftTop.Y));
        //创建截取图片对象
        var wb = new WriteableBitmap(rect.Width, rect.Height, 0, 0, screenWb.Format, null);
        //写入截取区域数据
        wb.WritePixels(rect, screenWb.BackBuffer, screenWb.PixelHeight * screenWb.BackBufferStride, screenWb.BackBufferStride, 0, 0);
        return wb;
    }
    return null;
}

 Clipboard.SetImage(GetClipImage());