Add SortMemberPath to TableViewColumn for custom sorting

Author: cricketthomas

src/Columns/TableViewColumn.cs

@@ -455,6 +455,21 @@ private static void OnHeaderStyleChanged(DependencyObject d, DependencyPropertyC
         }
     }
 
+    /// <summary>
+    /// Gets or sets the member path to use for sorting instead of the default binding path.
+    /// Holds the name of the member to use for sorting, if not using the default.
+    /// </summary>
+    public string? SortMemberPath
+    {
+        get => (string?)GetValue(SortMemberPathProperty);
+        set => SetValue(SortMemberPathProperty, value);
+    }
+
+    /// <summary>
+    /// Identifies the SortMemberPath dependency property.
+    /// </summary>
+    public static readonly DependencyProperty SortMemberPathProperty = DependencyProperty.Register(nameof(SortMemberPath), typeof(string), typeof(TableViewColumn), new PropertyMetadata(null));
+
     /// <summary>
     /// Identifies the HeaderStyle dependency property.
     /// </summary>

src/ItemsSource/ColumnSortDescription.cs

@@ -21,6 +21,11 @@ public ColumnSortDescription(TableViewColumn column,
 
     public override object? GetPropertyValue(object? item)
     {
+        // If a property name SortMemberPath was provided
+        if (!string.IsNullOrEmpty(PropertyName))
+        {
+            return base.GetPropertyValue(item);
+        }
         return Column.GetCellContent(item);
     }
 

src/TableViewColumnHeader.cs

@@ -111,8 +111,12 @@ private void DoSort(SD? direction, bool singleSorting = true)
                 {
                     var boundColumn = Column as TableViewBoundColumn;
                     Column.SortDirection = direction;
+
+                    // Prefer explicit SortMemberPath if provided, otherwise use bound column's property path
+                    var sortPath = Column.SortMemberPath ?? boundColumn?.PropertyPath;
+
                     _tableView.SortDescriptions.Add(
-                        new ColumnSortDescription(Column!, boundColumn?.PropertyPath, direction.Value));
+                        new ColumnSortDescription(Column!, sortPath, direction.Value));
 
                     _tableView.EnsureAlternateRowColors();
                 }