原因：wpf裏 popup不能超過屏幕75%的面積，不知道為什麽要這麽設置？

修改方法：

 1 private void SetPopupScreen()
 2         {
 3             Rect rtWnd = new Rect(0, 0, gridMainArea.ActualWidth, gridMainArea.ActualHeight);
 4             DependencyObject parent = popPatientInfos.Child;
 5             do
 6             {
 7                 parent = VisualTreeHelper.GetParent(parent);
 
 8                 if (parent != null && parent.ToString() == "System.Windows.Controls.Primitives.PopupRoot")
 9                 {
10                     var element = parent as FrameworkElement;
11                     element.Width = gridMainArea.ActualWidth;//根據需要修改寬高
12                     element.Height = gridMainArea.ActualHeight;
 
13                     rtWnd = new Rect(0, 0, element.Width, element.Height);
14                     popPatientInfos.PlacementRectangle = rtWnd;
15                     break;
16                 }
17             }
18             while (parent != null);
19         }

WPF popup被截斷的原因和修改方法