Initial commit

ExtendedListBoxControl/ExtendedListBox.cs

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+using System.Windows;
+using System.Windows.Controls;
+
+namespace Common.Wpf.ExtendedListBoxControl
+{
+    public class ExtendedListBox : ListBox
+    {
+        protected override DependencyObject GetContainerForItemOverride()
+        {
+            return new ExtendedListBoxItem();
+        }
+
+        private int _lastSelectedIndex = -1;
+
+        protected override void OnSelectionChanged(SelectionChangedEventArgs e)
+        {
+            base.OnSelectionChanged(e);
+
+            if (SelectedIndex == -1 && _lastSelectedIndex != -1)
+            {
+                int itemCount = Items.Count;
+
+                if (_lastSelectedIndex >= itemCount)
+                    _lastSelectedIndex = itemCount - 1;
+
+                SelectedIndex = _lastSelectedIndex;
+            }
+
+            _lastSelectedIndex = SelectedIndex;
+        }
+    }
+}

ExtendedListBoxControl/ExtendedListBoxItem.cs

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+using System.Windows.Controls;
+using System.Windows.Input;
+
+using Common.Wpf.Extensions;
+
+namespace Common.Wpf.ExtendedListBoxControl
+{
+    public class ExtendedListBoxItem : ListBoxItem
+    {
+        #region Helper properties
+
+        public ExtendedListBox ParentListBox
+        {
+            get
+            {
+                return this.GetAncestor<ExtendedListBox>();
+            }
+        }
+
+        #endregion
+
+        #region Fix selection handling for multiple selection
+
+        private bool _fireMouseDownOnMouseUp;
+        private SelectionMode? _selectionMode;
+
+        private SelectionMode SelectionMode
+        {
+            get
+            {
+                if (_selectionMode == null)
+                {
+                    // Get the parent list box
+                    ListBox listBox = ParentListBox;
+
+                    // Cache the selection mode
+                    _selectionMode = listBox.SelectionMode;
+                }
+
+                return _selectionMode.Value;
+            }
+        }
+
+        protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
+        {
+            // If the item is already selected we want to ignore the mouse down now and raise it on mouse up instead
+            if (SelectionMode != SelectionMode.Single && IsSelected)
+            {
+                _fireMouseDownOnMouseUp = true;
+                return;
+            }
+
+            // Call the normal mouse down
+            base.OnMouseLeftButtonDown(e);
+        }
+
+        protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
+        {
+            // If we ignored the earlier mouse down we need to fire it now
+            if (SelectionMode != SelectionMode.Single && _fireMouseDownOnMouseUp)
+            {
+                // Call the normal mouse down
+                base.OnMouseLeftButtonDown(e);
+
+                // Clear the flag
+                _fireMouseDownOnMouseUp = false;
+            }
+
+            // Call the normal mouse up
+            base.OnMouseLeftButtonUp(e);
+        }
+
+        #endregion
+    }
+}