Citrix环境下VSTO Excel插件WPF窗体跨显示器拖动后空白的解决方法

以下是针对该问题的几种有效解决方案：

• 强制WPF控件适配当前DPI
  Citrix环境切换屏幕时，显示设备的DPI可能发生变化，导致WPF控件渲染异常。可在WpfContainerForm的构造函数中添加DPI适配逻辑：

  // 在初始化objPrepareView后添加
  var presentationSource = PresentationSource.FromVisual(objPrepareView);
  if (presentationSource != null)
  {
      var dpiScaleX = presentationSource.CompositionTarget.TransformToDevice.M11;
      var dpiScaleY = presentationSource.CompositionTarget.TransformToDevice.M22;
      objPrepareView.LayoutTransform = new ScaleTransform(dpiScaleX, dpiScaleY);
  }
  

  也可在显示窗体前先触发一次布局更新：

  prepareViewForm.Show();
  objPrepareView.UpdateLayout();
  prepareViewForm.Hide();
  var result = prepareViewForm.ShowDialog();
  

• 基于Excel窗口所在屏幕手动定位窗体
  避免CenterParent在跨屏幕场景下的定位偏差，改为获取Excel窗口所在屏幕并计算居中位置：

  var excelWindowHandle = Globals.ThisAddIn.Application.MainWindowHandle;
  var targetScreen = Screen.FromHandle(excelWindowHandle);
  
  prepareViewForm.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
  int posX = targetScreen.Bounds.Left + (targetScreen.Bounds.Width - prepareViewForm.Width) / 2;
  int posY = targetScreen.Bounds.Top + (targetScreen.Bounds.Height - prepareViewForm.Height) / 2;
  prepareViewForm.Location = new System.Drawing.Point(posX, posY);
  

• 禁用WPF硬件加速
  Citrix虚拟显示环境常与WPF硬件加速存在兼容问题，可全局或针对单个窗体禁用：

  // 全局禁用（建议在WPF控件初始化前添加）
  System.Windows.Media.RenderOptions.ProcessRenderMode = System.Windows.Media.RenderMode.SoftwareOnly;
  
  // 或针对单个WPF窗体禁用
  var windowInteropHelper = new System.Windows.Interop.WindowInteropHelper(objPrepareView);
  var hwndSource = System.Windows.Interop.HwndSource.FromHwnd(windowInteropHelper.Handle);
  if (hwndSource != null)
  {
      hwndSource.CompositionTarget.RenderMode = System.Windows.Media.RenderMode.SoftwareOnly;
  }
  

• 监听容器Resize事件触发重绘
  屏幕切换时WinForms容器会触发Resize事件，此时手动强制WPF控件重绘：

  prepareViewForm.Resize += (sender, e) =>
  {
      objPrepareView.InvalidateVisual();
      objPrepareView.UpdateLayout();
  };
  

内容的提问来源于stack exchange，提问作者Abhishek Bali