增加工单模块

OrderSupportTicket/Behaviors/ListBoxInteractionBehavior.cs

@@ -0,0 +1,121 @@
+using System;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Threading;
+
+namespace OrderSupportTicket.Behaviors;
+
+/// <summary>
+/// 仅承载视图交互：列表点击命令、消息列表滚动到底部。
+/// </summary>
+public static class ListBoxInteractionBehavior
+{
+    public static readonly DependencyProperty SelectedItemCommandProperty =
+        DependencyProperty.RegisterAttached(
+            "SelectedItemCommand",
+            typeof(ICommand),
+            typeof(ListBoxInteractionBehavior),
+            new PropertyMetadata(null, OnSelectedItemCommandChanged));
+
+    public static readonly DependencyProperty ScrollVersionProperty =
+        DependencyProperty.RegisterAttached(
+            "ScrollVersion",
+            typeof(int),
+            typeof(ListBoxInteractionBehavior),
+            new PropertyMetadata(0, OnScrollVersionChanged));
+
+    public static void SetSelectedItemCommand(DependencyObject element, ICommand value)
+    {
+        element.SetValue(SelectedItemCommandProperty, value);
+    }
+
+    public static ICommand GetSelectedItemCommand(DependencyObject element)
+    {
+        return (ICommand)element.GetValue(SelectedItemCommandProperty);
+    }
+
+    public static void SetScrollVersion(DependencyObject element, int value)
+    {
+        element.SetValue(ScrollVersionProperty, value);
+    }
+
+    public static int GetScrollVersion(DependencyObject element)
+    {
+        return (int)element.GetValue(ScrollVersionProperty);
+    }
+
+    private static void OnSelectedItemCommandChanged(
+        DependencyObject d,
+        DependencyPropertyChangedEventArgs e)
+    {
+        if (!(d is ListBox listBox))
+            return;
+
+        listBox.PreviewMouseLeftButtonUp -= OnPreviewMouseLeftButtonUp;
+        listBox.PreviewKeyUp -= OnPreviewKeyUp;
+        if (e.NewValue is ICommand)
+        {
+            listBox.PreviewMouseLeftButtonUp += OnPreviewMouseLeftButtonUp;
+            listBox.PreviewKeyUp += OnPreviewKeyUp;
+        }
+    }
+
+    private static void OnPreviewMouseLeftButtonUp(
+        object sender,
+        MouseButtonEventArgs e)
+    {
+        ExecuteForSelectedItem(sender as ListBox);
+    }
+
+    private static void OnPreviewKeyUp(object sender, KeyEventArgs e)
+    {
+        if (e.Key != Key.Enter && e.Key != Key.Space)
+            return;
+        ExecuteForSelectedItem(sender as ListBox);
+    }
+
+    private static void ExecuteForSelectedItem(ListBox listBox)
+    {
+        if (listBox == null || listBox.SelectedItem == null)
+            return;
+        var command = GetSelectedItemCommand(listBox);
+        if (command != null && command.CanExecute(listBox.SelectedItem))
+            command.Execute(listBox.SelectedItem);
+    }
+
+    private static void OnScrollVersionChanged(
+        DependencyObject d,
+        DependencyPropertyChangedEventArgs e)
+    {
+        if (!(d is ListBox listBox))
+            return;
+
+        listBox.Dispatcher.BeginInvoke(
+            new Action(() =>
+            {
+                var scrollViewer = FindVisualChild<ScrollViewer>(listBox);
+                if (scrollViewer != null)
+                    scrollViewer.ScrollToEnd();
+            }),
+            DispatcherPriority.Background);
+    }
+
+    private static T FindVisualChild<T>(DependencyObject parent)
+        where T : DependencyObject
+    {
+        if (parent == null)
+            return null;
+        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
+        {
+            var child = VisualTreeHelper.GetChild(parent, i);
+            if (child is T match)
+                return match;
+            var nested = FindVisualChild<T>(child);
+            if (nested != null)
+                return nested;
+        }
+        return null;
+    }
+}