Refactor pointer event handling for selection logic

Refactored TableView, TableViewCell, and TableViewRow to override OnPointerPressed/OnPointerReleased instead of using AddHandler. Updated selection and drag logic to use internal TableView.OnAnyPointerPressed, improving event distinction and consistency. Removed OnAnyPointerReleased and centralized drag selection ending. Enhanced handling for pointer events over scrollbars, headers, and invalid areas.

Author: w-ahmad

src/TableView.cs

@@ -77,9 +77,6 @@ public TableView()
         Unloaded += OnUnloaded;
         SelectionChanged += TableView_SelectionChanged;
         _collectionView.ItemPropertyChanged += OnItemPropertyChanged;
-
-        AddHandler(PointerPressedEvent, new PointerEventHandler(OnAnyPointerPressed), handledEventsToo: true);
-        AddHandler(PointerReleasedEvent, new PointerEventHandler(OnAnyPointerReleased), handledEventsToo: true);
     }
 
     /// <summary>
@@ -425,29 +422,49 @@ protected override void OnKeyDown(KeyRoutedEventArgs e)
         HandleNavigations(e, shiftKey, ctrlKey);
     }
 
+    /// <inheritdoc/>
+    protected override void OnPointerPressed(PointerRoutedEventArgs e)
+    {
+        base.OnPointerPressed(e);
+
+        var originalSource = e.OriginalSource as FrameworkElement;
+
+        if (originalSource?.FindAscendant<ScrollBar>() is not null          // Skip if the pointer is over a ScrollBar.
+            || originalSource?.FindAscendant<TableViewCell>() is not null   // Skip if the pointer is over a TableViewCell.
+            || originalSource?.FindAscendant<TableViewRow>() is not null)   // Skip if the pointer is over a TableViewRow.
+        {
+            return; 
+        }
+
+        OnAnyPointerPressed(this, e);
+    }
+
+    /// <inheritdoc/>
+    protected override void OnPointerReleased(PointerRoutedEventArgs e)
+    {
+        base.OnPointerReleased(e);
+
+        EndDragSelection();
+    }
+
     /// <summary>
     /// Handles pointer-pressed for all cases, including when elements sets <c>e.Handled = true</c>.
     /// </summary>
-    private void OnAnyPointerPressed(object sender, PointerRoutedEventArgs e)
+    internal void OnAnyPointerPressed(UIElement pressedElement, PointerRoutedEventArgs e)
     {
         var pointerPoint = e.GetCurrentPoint(this);
         var position = pointerPoint.Position;
         var canvasPoint = GetCanvasPoint(position);
         var ctrlKey = KeyboardHelper.IsCtrlKeyDown();
         var isShiftKey = KeyboardHelper.IsShiftKeyDown();
-        var orignalSoruce = e.OriginalSource as FrameworkElement;
-        UIElement? pressedElement = orignalSoruce?.FindAscendant<TableViewCell>();      // Check if the pointer is over a cell
-        pressedElement ??= orignalSoruce?.FindAscendant<TableViewRow>();                // If not, check if the pointer is over a row
 
         if (SelectionMode is ListViewSelectionMode.None                                 // Skip selection when SelectionMode is None
             || IsDragSelecting                                                          // Skip selection when a drag is already in progress
-            || orignalSoruce is ScrollBar                                               // Skip selection when the pointer is over the ScrollBar
-            || orignalSoruce?.FindAscendant<ScrollBar>() is { }                         // Skip selection when the pointer is within a ScrollBar
-            || (pressedElement == null && !ShowDragRectangle)                           // Skip selection when the pointer is not over a Cell or Row, and ShowDragRectangle is false.
-            || !pointerPoint.Properties.IsLeftButtonPressed                             // Skip selection when the left mouse button is not pressed
             || canvasPoint is null                                                      // Skip selection when canvasPoint is null (e.g., pointer is outside the scroll canvas)
-            || canvasPoint.Value.Y < 0                                                  // Skip selection when the pointer is in the column header area (above the scroll canvas)              
-            || (pressedElement == null && canvasPoint.Value.X < CellsHorizontalOffset)  // Skip selection when the pointer is in the row header area (and not on a row/cell)
+            || canvasPoint.Value.Y < 0                                                  // Skip selection when the pointer is in the column header area (above the scroll canvas)
+            || !pointerPoint.Properties.IsLeftButtonPressed                             // Skip selection when the left mouse button is not pressed
+            || (pressedElement == this && !ShowDragRectangle)                           // Skip selection when the pointer is not over a Cell or Row, and ShowDragRectangle is false.
+            || (pressedElement != this && canvasPoint.Value.X < CellsHorizontalOffset)  // Skip selection when the pointer is in the row header area (and not on the TableView)
             || isShiftKey)                                                              // Skip selection when the Shift key is held
         {
             return;
@@ -462,7 +479,7 @@ private void OnAnyPointerPressed(object sender, PointerRoutedEventArgs e)
         LastSelectionUnit = TableViewSelectionUnit.Row;
 #if !WINDOWS
         _dragStartCell = pressedElement as TableViewCell;
-        _dragStartRow = (pressedElement as TableViewRow) ?? orignalSoruce?.FindAscendant<TableViewRow>();
+        _dragStartRow = (pressedElement as TableViewRow) ?? pressedElement?.FindAscendant<TableViewRow>();
 #endif
         pressedElement ??= this; // If not, default to the TableView itself
 
@@ -805,14 +822,6 @@ private void SelectCellsInDragRect(TableViewCellSlotRange cells)
         });
     }
 
-    /// <summary>
-    /// Handles pointer-released for all cases, including when elements sets <c>e.Handled = true</c>.
-    /// </summary>
-    private void OnAnyPointerReleased(object sender, PointerRoutedEventArgs e)
-    {
-        EndDragSelection();
-    }
-
     /// <summary>
     /// Handles navigation keys.
     /// </summary>

src/TableViewCell.cs

@@ -422,7 +422,10 @@ protected override void OnPointerPressed(PointerRoutedEventArgs e)
             e.Handled = true;
             return;
         }
+
+        TableView?.OnAnyPointerPressed(this, e);
     }
+
     /// <inheritdoc/>
     protected override void OnPointerReleased(PointerRoutedEventArgs e)
     {
@@ -432,6 +435,8 @@ protected override void OnPointerReleased(PointerRoutedEventArgs e)
         {
             e.Handled = true;
         }
+
+        TableView?.EndDragSelection();
     }
 
     /// <summary>

src/TableViewRow.cs

@@ -195,6 +195,22 @@ protected override Size ArrangeOverride(Size finalSize)
         return finalSize;
     }
 
+    /// <inheritdoc/>
+    protected override void OnPointerPressed(PointerRoutedEventArgs e)
+    {
+        base.OnPointerPressed(e);
+
+        TableView?.OnAnyPointerPressed(this, e);
+    }
+
+    /// <inheritdoc/>
+    protected override void OnPointerReleased(PointerRoutedEventArgs e)
+    {
+        base.OnPointerReleased(e);
+
+        TableView?.EndDragSelection();
+    }
+
     /// <summary>
     /// Updates the position of the row relative to the TableView.
     /// </summary>