优化更新代码，添加界面功能并整合

WPFluent/Controls/TreeModelListView/TreeModelListViewItem.cs

@@ -0,0 +1,101 @@
+using System.ComponentModel;
+using System.Windows.Controls;
+using System.Windows.Input;
+
+namespace WPFluent.Controls;
+
+public class TreeModelListViewItem : ListViewItem, INotifyPropertyChanged
+{
+    private TreeModelNode? _node;
+
+    public TreeModelNode? Node
+    {
+        get => _node;
+        internal set
+        {
+            _node = value;
+            OnPropertyChanged(nameof(Node));
+        }
+    }
+
+    public TreeModelListViewItem()
+    {
+    }
+
+    protected override void OnKeyDown(KeyEventArgs e)
+    {
+        if (Node != null)
+        {
+            switch (e.Key)
+            {
+                case Key.Right:
+                    e.Handled = true;
+                    if (!Node.IsExpanded)
+                    {
+                        Node.IsExpanded = true;
+                        ChangeFocus(Node);
+                    }
+                    else if (Node.Children.Count > 0)
+                    {
+                        ChangeFocus(Node.Children[0]);
+                    }
+
+                    break;
+
+                case Key.Left:
+
+                    e.Handled = true;
+                    if (Node.IsExpanded && Node.IsExpandable)
+                    {
+                        Node.IsExpanded = false;
+                        ChangeFocus(Node);
+                    }
+                    else
+                    {
+                        ChangeFocus(Node.Parent);
+                    }
+
+                    break;
+
+                case Key.Subtract:
+                    e.Handled = true;
+                    Node.IsExpanded = false;
+                    ChangeFocus(Node);
+                    break;
+
+                case Key.Add:
+                    e.Handled = true;
+                    Node.IsExpanded = true;
+                    ChangeFocus(Node);
+                    break;
+            }
+        }
+
+        if (!e.Handled)
+        {
+            base.OnKeyDown(e);
+        }
+    }
+
+    private void ChangeFocus(TreeModelNode? node)
+    {
+        if (node?.Tree is TreeModelListView { } tree)
+        {
+            if (tree.ItemContainerGenerator.ContainerFromItem(node) is TreeModelListViewItem item)
+            {
+                item.Focus();
+            }
+            else
+            {
+                tree.PendingFocusNode = node;
+            }
+        }
+    }
+
+    public event PropertyChangedEventHandler? PropertyChanged;
+
+    private void OnPropertyChanged(string name)
+    {
+        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
+    }
+}