具有多选的 WPF TreeView

Question

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9年前关闭。




标准 WPF tree view不支持多选。

如何向我的 WPF 应用程序添加支持多选的 TreeView ？商业产品很好(我目前知道一种商业实现 - http://www.telerik.com/products/wpf/treeview.aspx)

Answer 1

下面的代码工作正常，而且更简单。然而，缺点是 TreeView 类的非公共(public)属性 IsSelectionChangeActive 的使用。下面的代码:

private static readonly PropertyInfo IsSelectionChangeActiveProperty 
  = typeof (TreeView).GetProperty
    (
      "IsSelectionChangeActive",
      BindingFlags.NonPublic | BindingFlags.Instance
    );

public static void AllowMultiSelection(TreeView treeView)
{
  if (IsSelectionChangeActiveProperty==null) return;

  var selectedItems = new List<TreeViewItem>();
  treeView.SelectedItemChanged += (a, b) =>
  {
    var treeViewItem = treeView.SelectedItem as TreeViewItem;
    if (treeViewItem == null) return;

    // allow multiple selection
    // when control key is pressed
    if (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl))
    {
      // suppress selection change notification
      // select all selected items
      // then restore selection change notifications
      var isSelectionChangeActive = 
        IsSelectionChangeActiveProperty.GetValue(treeView, null);

      IsSelectionChangeActiveProperty.SetValue(treeView, true, null);
      selectedItems.ForEach(item => item.IsSelected = true);

      IsSelectionChangeActiveProperty.SetValue
      (
        treeView, 
        isSelectionChangeActive, 
        null
      );
    }
    else
    {
      // deselect all selected items except the current one
      selectedItems.ForEach(item => item.IsSelected = (item == treeViewItem) );
      selectedItems.Clear();
    }

    if (!selectedItems.Contains(treeViewItem))
    {
      selectedItems.Add(treeViewItem);
    }
    else
    {
      // deselect if already selected
      treeViewItem.IsSelected = false;
      selectedItems.Remove(treeViewItem);
    }
  };

}