Update ComboBoxHelper.cs

handle cornerradius

Update ComboBoxHelper.cs

better vertical offset calculation

Update ComboBoxHelper.cs

clean

clean

Update ComboBoxHelper.cs

better vertical offset calculation

Update ComboBoxHelper.cs

clean

clean

Author: mou-haz

source/iNKORE.UI.WPF.Modern/Controls/Helpers/ComboBoxHelper.cs

@@ -5,7 +5,6 @@
 using iNKORE.UI.WPF.Modern.Common.Converters;
 using System.Windows;
 using System.Windows.Controls;
-using System.Windows.Threading;
 
 namespace iNKORE.UI.WPF.Modern.Controls.Helpers
 {
@@ -113,10 +112,20 @@ private static void UpdateCornerRadius(ComboBox comboBox, bool isDropDownOpen)
 
             if (isDropDownOpen)
             {
-                bool isOpenDown = IsPopupOpenDown(comboBox);
+                var popup = GetTemplateChild<System.Windows.Controls.Primitives.Popup>("PART_Popup", comboBox);
+                bool isOpenDown = IsPopupOpenDown(comboBox, popup.VerticalOffset);
 
-                var popupRadiusFilter = isOpenDown ? CornerRadiusFilterKind.Bottom : CornerRadiusFilterKind.Top;
-                popupRadius = CornerRadiusFilterConverter.Convert(popupRadius, popupRadiusFilter);
+                if (isOpenDown &&
+                    comboBox.ItemContainerGenerator.ContainerFromItem(comboBox.SelectedItem) is FrameworkElement itemContainer &&
+                    itemContainer.TranslatePoint(new Point(0, -itemContainer.ActualHeight + comboBox.Margin.Top + comboBox.Padding.Top), comboBox) is { Y: not 0 } itemTop)
+                {
+                    popup.VerticalOffset -= itemTop.Y;
+                }
+
+                if (popup.VerticalOffset is 0)
+                {
+                    popupRadius = GetFilteredPopupRadius(popupRadius, isOpenDown);
+                }
 
                 var textBoxRadiusFilter = isOpenDown ? CornerRadiusFilterKind.Top : CornerRadiusFilterKind.Bottom;
                 textBoxRadius = CornerRadiusFilterConverter.Convert(textBoxRadius, textBoxRadiusFilter);
@@ -148,9 +157,15 @@ private static void UpdateCornerRadius(ComboBox comboBox, bool isDropDownOpen)
             }
         }
 
-        private static bool IsPopupOpenDown(ComboBox comboBox)
+        private static CornerRadius GetFilteredPopupRadius(CornerRadius popupRadius, bool isOpenDown)
+        {
+            var popupRadiusFilter = isOpenDown ? CornerRadiusFilterKind.Bottom : CornerRadiusFilterKind.Top;
+            return CornerRadiusFilterConverter.Convert(popupRadius, popupRadiusFilter);
+        }
+
+        private static bool IsPopupOpenDown(ComboBox comboBox, double popupVerticalOffset)
         {
-            double verticalOffset = 0;
+            double verticalOffset = popupVerticalOffset;
             if (GetTemplateChild<Border>(c_popupBorderName, comboBox) is Border popupBorder)
             {
                 if (GetTemplateChild<TextBox>(c_editableTextName, comboBox) is TextBox textBox)
@@ -159,7 +174,7 @@ private static bool IsPopupOpenDown(ComboBox comboBox)
                     verticalOffset = popupTop.Y;
                 }
             }
-            return verticalOffset > 0;
+            return verticalOffset > popupVerticalOffset;
         }
 
         private static object ResourceLookup(Control control, object key)