c# - WPF， TreeView 选择更改

Question

有没有办法捕获更改 WPF 的 TreeView 中当前选定项目的尝试并可能取消它？

TreeView 中的元素表示具有某些属性的页面。我想询问用户是否要放弃在页面上所做的更改、保存它们或留在当前页面。

Answer 1

对于更简单的解决方案。覆盖 PreviewMouseDown，您将获得所需的结果。

 private void Tree_OnPreviewMouseDown(object sender, MouseButtonEventArgs e)
    {
        // first did the user click on a tree node?
        var source = e.OriginalSource as DependencyObject;
        while (source != null && !(source is TreeViewItem))
            source = VisualTreeHelper.GetParent(source);
        source = source as TreeViewItem;
        if (source == null) return;

        var treeView = sender as TreeView;
        if (treeView == null) return;

        // validate our current item to decide if we allow the change
        // or do whatever checks you wish
        if (!ItemIsValid(treeView.SelectedItem))
        {
            // it's not valid, so cancel the attempt to select an item.
            e.Handled = true;
        }

        // Maybe you want to check the about to be selected value?
        MyClass data = source.DataContext;
        if (!CanSelect(data))
        {
            // we can't select this, so cancel the attempt to select.
            e.Handled = true;
        }
    }