在 TreeViewItem_OnExpanded 事件中,我有以下代码。
var expandedTreeViewItem = e.OriginalSource as TreeViewItem;
var child = expandedTreeViewItem.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
expandedTreeViewItem.ItemsSource = // Update ItemsSource
var child = expandedTreeViewItem.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
在更改展开的树视图项的ItemSource之前获取孩子没有问题,但是在更改ItemSource之后,孩子将为空。
ContainerFromItem(item) 中的item 是相同的,并且在更改ItemSource 之前和之后都存在。代码的其他部分正常工作。在 ItemSource 更改后,我该怎么做才能获取元素?
TreeViewItem_OnExpanded 事件代码
private void TreeViewItem_OnExpanded(object sender, RoutedEventArgs e)
{
var expandedTreeViewItem = e.OriginalSource as TreeViewItem;
var directoryInfo = expandedTreeViewItem?.Items[0] as DirectoryInfoModel;
if (expandedTreeViewItem == null || directoryInfo?.HasChild == false) return;
_folderExplorerViewModel.GetDirectories(directoryInfo?.DirectoryInfo, directoryInfo?.SubDirectoriesCollection);
expandedTreeViewItem.ItemsSource = directoryInfo?.SubDirectoriesCollection;
var expandedItemHeader = expandedTreeViewItem?.Template.FindName("PART_Header", expandedTreeViewItem) as ContentPresenter;
var expandedItemCheckBox = expandedItemHeader?.ContentTemplate.FindName("CheckBoxFolderItem", expandedItemHeader) as CheckBox;
foreach (var item in expandedTreeViewItem.Items)
{
var childItem = expandedTreeViewItem.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
var childHeader = childItem?.Template.FindName("PART_Header", childItem) as ContentPresenter;
var childCheckBox = childHeader?.ContentTemplate.FindName("CheckBoxFolderItem", childHeader) as CheckBox;
if (childCheckBox != null && expandedItemCheckBox != null)
{
childCheckBox.IsChecked = expandedItemCheckBox.IsChecked;
}
}
}
在 ItemesSource 更改后使用 childItem 时,它始终为 null。但在此之前,它有效。
非常感谢。