WPF树视图蓝色.我想选一件商品
本文关键字：一件 视图 蓝色 WPF | 更新日期: 2023-09-27 18:01:22
我正在尝试选择一个TreeViewItem。现在，我可以访问包含TreeViewItem并告诉它展开，这样我就可以选择它的子元素。如果已经展开，则一切正常，如果没有，则运行以下代码:
EventHandler selector = new EventHandler(delegate
{
if (selectedDirectoryTreeItem.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
TreeViewItem want = selectedDirectoryTreeItem.ItemContainerGenerator.ContainerFromItem(dirWeWantSelected) as TreeViewItem;
if (want == null)
return;
want.IsSelected = true;
// selectedDirectoryTreeItem.ItemContainerGenerator.StatusChanged -= selector;
}
});
selectedDirectoryTreeItem.ItemContainerGenerator.StatusChanged += selector;
我的问题是，为什么它不选择?"想要"总是空的。我正在网上寻找另一种方法但是如果有人能给我解释一下就太好了
我个人总是发现最简单的方法是将一个Selected属性粘贴到我的模型对象中，然后将TreeViewItem Selected属性绑定到模型的Selected属性。下面是一些代码:
模型public class Data : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public Data()
{
DataItems = new List<Data>();
}
public string Name { get; set; }
private bool _selected;
public bool Selected
{
get { return _selected; }
set
{
_selected = value;
OnPropertyChanged("Selected");
}
}
public List<Data> DataItems { get; set; }
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
XAML
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
xmlns:controls="clr-namespace:MyControls;assembly=MyControls"
Title="Window1">
<Window.Resources>
<Style x:Key="CustomTreeViewItem" TargetType="TreeViewItem">
<Setter Property="IsSelected" Value="{Binding Path=Selected, Mode=TwoWay}" />
<Setter Property="IsExpanded" Value="True" />
</Style>
</Window.Resources>
<DockPanel Background="Transparent">
<TreeView x:Name="_tvTest" DockPanel.Dock="Left" ItemContainerStyle="{StaticResource CustomTreeViewItem}" Width="300" >
<TreeView.ItemTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:Data}" ItemsSource="{Binding DataItems}">
<TextBlock Text="{Binding Name}" Padding="2" />
<HierarchicalDataTemplate.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" Padding="2" />
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<Button Content="Select Random TreeView Item" Click="Button_Click" Height="50" Width="200" />
</DockPanel>
</Window>
public partial class Window1 : Window
{
private Random _random;
private List<Data> _dataItems;
public Window1()
{
InitializeComponent();
_dataItems = Init();
_tvTest.ItemsSource = _dataItems;
_random = new Random(5);
}
private List<Data> Init()
{
List<Data> dataItems = new List<Data>();
for (int i = 1; i <= 10; i++)
{
Data d1 = new Data();
d1.Name = "Data:" + i.ToString();
for (int j = 1; j <= 4; j++)
{
Data d2 = new Data();
d2.Name = "Data:" + i.ToString() + j.ToString();
d1.DataItems.Add(d2);
}
dataItems.Add(d1);
}
return dataItems;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
int index = _random.Next(0, 9);
int subIndex = _random.Next(0, 3);
if (subIndex == 0)
_dataItems[index].Selected = true;
else
_dataItems[index].DataItems[subIndex - 1].Selected = true;
}
}
在我看来，这是WPF的一个bug，但是我已经遇到过同样的问题好几次了。我从不相信ItemContainerGenerator的状态，而是在单独的线程上循环，如下所示:
private void _selectTreeViewHelper(object directory) {
TreeViewItem want = null;
bool broke = false; //probably some sort of wait timeout instead, but works for sake of example
while (true) {
Dispatcher.Invoke(new Action(delegate {
want = selectedDirectoryTreeItem.ItemContainerGenerator.ContainerFromItem(directory) as TreeViewItem;
if (want != null && want.IsLoaded) {
want.IsSelected = true;
broke = true;
}
}));
if (broke) { break; }
Thread.Sleep(100);
}
}
然后调用:
var thread = new Thread(new ParameterizedThreadStart(_selectTreeViewHelper));
thread.Start(dirWeWantSelected);
痛苦我知道，但它有效。
谢谢你的帮助，我明白了。好吧，不管怎样，它是有效的，但我不完全确定为什么它之前没有…如果有人能告诉我，那就太好了……我结合了上面两种回答的元素，然后添加了一点使其有效。出于某种原因，无论我做什么，我不能选择TVI (TreeViewElement)，如果它的父还没有展开，即使父TVI说它的内容是生成的，事实上，有内容我可以遍历。因此，我的解决方案是等待生成内容，然后遍历它们并找到我想要的内容。这对我来说真的很奇怪，我不能抓住一个容器，因为它的内容。咩。我的代码可以稍微重构一下，但这里是:(工作完美)
public void listItemClickClick(object sender, RoutedEventArgs e)
{
try
{
UserFile fil = (UserFile)(sender as ListBoxItem).DataContext;
MessageBox.Show("to do: download stuff");
return;
}
catch (InvalidCastException)
{
}
try
{
dirWeWantSelected = (Directory)(sender as ListBoxItem).DataContext;
}
catch (InvalidCastException)
{
MessageBox.Show("this should never happen");
}
selectedDirectoryTreeItem.IsExpanded = true;
TreeViewItem want = null;
try
{
want = selectedDirectoryTreeItem.ItemContainerGenerator.ContainerFromItem(dirWeWantSelected) as TreeViewItem;
}
catch
{
MessageBox.Show("weird error");
}
if (want != null)
{
want.IsSelected = true;
}
else
{
selectedDirectoryTreeItem.ItemContainerGenerator.StatusChanged += ItemContainerGenerator_StatusChanged;
}
}
void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
{
if (selectedDirectoryTreeItem.ItemContainerGenerator.Status
== System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated)
{
selectedDirectoryTreeItem.ItemContainerGenerator.StatusChanged
-= ItemContainerGenerator_StatusChanged;
Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Input,
new Action(DelayedAction));
}
}
void DelayedAction()
{
selectedDirectoryTreeItem.Items.MoveCurrentToFirst();
Directory curr;
do
{
curr = (Directory)selectedDirectoryTreeItem.Items.CurrentItem;
if (curr.id == dirWeWantSelected.id)
{
curr.Selected = true;
return;
}
selectedDirectoryTreeItem.Items.MoveCurrentToNext();
}
while (selectedDirectoryTreeItem.Items.CurrentItem != null);
}