如何检索在WPF-treeview中选择的项?我想在XAML中这样做，因为我想绑定它。
您可能认为它是SelectedItem，但显然它不存在是只读的，因此不可用。
这就是我想做的:
<TreeView ItemsSource="{Binding Path=Model.Clusters}"
ItemTemplate="{StaticResource ClusterTemplate}"
SelectedItem="{Binding Path=Model.SelectedCluster}" />
我想将SelectedItem绑定到我的Model上的一个属性。
但这给了我一个错误:
“SelectedItem”属性是只读的，不能从标记中设置。
编辑:
这就是我解决这个问题的方法:
<TreeView
ItemsSource="{Binding Path=Model.Clusters}"
ItemTemplate="{StaticResource HoofdCLusterTemplate}"
SelectedItemChanged="TreeView_OnSelectedItemChanged" />
在我的xaml的代码背后文件:
private void TreeView_OnSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
Model.SelectedCluster = (Cluster)e.NewValue;
}
我意识到这已经有了一个被接受的答案，但我把这些放在一起来解决问题。它使用了与Delta的解决方案类似的思想，但不需要子类化TreeView:
public class BindableSelectedItemBehavior : Behavior<TreeView>
{
#region SelectedItem Property
public object SelectedItem
{
get { return (object)GetValue(SelectedItemProperty); }
set { SetValue(SelectedItemProperty, value); }
}
public static readonly DependencyProperty SelectedItemProperty =
DependencyProperty.Register("SelectedItem", typeof(object), typeof(BindableSelectedItemBehavior), new UIPropertyMetadata(null, OnSelectedItemChanged));
private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
var item = e.NewValue as TreeViewItem;
if (item != null)
{
item.SetValue(TreeViewItem.IsSelectedProperty, true);
}
}
#endregion
protected override void OnAttached()
{
base.OnAttached();
this.AssociatedObject.SelectedItemChanged += OnTreeViewSelectedItemChanged;
}
protected override void OnDetaching()
{
base.OnDetaching();
if (this.AssociatedObject != null)
{
this.AssociatedObject.SelectedItemChanged -= OnTreeViewSelectedItemChanged;
}
}
private void OnTreeViewSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
this.SelectedItem = e.NewValue;
}
}
然后你可以在你的XAML中使用它:
<TreeView>
<e:Interaction.Behaviors>
<behaviours:BindableSelectedItemBehavior SelectedItem="{Binding SelectedItem, Mode=TwoWay}" />
</e:Interaction.Behaviors>
</TreeView>
希望它能帮助到一些人!
也可以使用TreeView项的IsSelected属性来完成。我是这么做的，
public delegate void TreeviewItemSelectedHandler(TreeViewItem item);
public class TreeViewItem
{
public static event TreeviewItemSelectedHandler OnItemSelected = delegate { };
public bool IsSelected
{
get { return isSelected; }
set
{
isSelected = value;
if (value)
OnItemSelected(this);
}
}
}
然后在包含TreeView绑定到的数据的ViewModel中，只需订阅TreeViewItem类中的事件。
TreeViewItem.OnItemSelected += TreeViewItemSelected;
最后，在同一个ViewModel中实现这个处理器，
private void TreeViewItemSelected(TreeViewItem item)
{
//Do something
}
当然，绑定，
<Setter Property="IsSelected" Value="{Binding IsSelected}" />
当点击某些项目列表时，你会在“选定”属性中获得数据。
视图模型:
public class ShellViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
private ObservableCollection<Books> _books;
private List<Books> bookList = new List<Books>();
public ObservableCollection<Books> Books
{
get { return _books; }
set { _books = value; NotifyPropertyChanged("Books"); }
}
private Books books;
public Books Selected
{
get { return books; }
set { books = value; }
}
public ShellViewModel()
{
bookList = new List<Books>()
{
new Books{BookName = "Harry Poter",Price ="15$"},
new Books{BookName = "Harry Poter 2 ",Price ="14.95$"},
new Books{BookName = "Harry Poter 3",Price ="18.50$"},
new Books{BookName = "Harry Poter 4",Price ="32.90$"},
};
Books = new ObservableCollection<Books>(bookList);
}
}
public class Books
{
public string BookName { get; set; }
public string Price { get; set; }
}
XAML:
<ListView x:Name="lst" Grid.Row="2" ItemsSource="{Binding Books}" SelectedItem="{Binding Selected}">
<ListView.View>
<GridView >
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding BookName}" />
<GridViewColumn Header="Price" Width="100" DisplayMemberBinding="{Binding Price}"/>
</GridView>
</ListView.View>
</ListView>
我提出了这个解决方案(我认为这是最简单的，并且没有内存泄漏)，它非常适合从视图的选定项更新ViewModel的选定项。
请注意，从ViewModel中更改所选项不会更新视图中的所选项。
public class TreeViewEx : TreeView
{
public static readonly DependencyProperty SelectedItemExProperty = DependencyProperty.Register("SelectedItemEx", typeof(object), typeof(TreeViewEx), new FrameworkPropertyMetadata(default(object))
{
BindsTwoWayByDefault = true // Required in order to avoid setting the "BindingMode" from the XAML
});
public object SelectedItemEx
{
get => GetValue(SelectedItemExProperty);
set => SetValue(SelectedItemExProperty, value);
}
protected override void OnSelectedItemChanged(RoutedPropertyChangedEventArgs<object> e)
{
SelectedItemEx = e.NewValue;
}
}
XAML usage
<l:TreeViewEx ItemsSource="{Binding Path=Items}" SelectedItemEx="{Binding Path=SelectedItem}" >
我知道这个帖子已经10年了，但问题仍然存在....
最初的问题是“检索”所选项目。我还需要在我的视图模型中“获取”选定的项目(而不是设置它)。在这个线程中的所有答案中，“Wes”的答案是唯一一个以不同的方式解决问题的答案:如果你可以使用“Selected Item”作为数据绑定的目标，那么就使用它作为数据绑定的源。Wes对另一个视图属性做过，我将对viewmodel属性做
我们需要两样东西:
在视图模型中创建一个依赖属性(在我的情况下，类型为'MyObject'，因为我的树视图绑定到'MyObject'类型的对象)
从Treeview绑定。SelectedItem属性在视图的构造函数中(是的，这是后面的代码，但很可能你也会init你的datacontext)
Viewmodel:
public static readonly DependencyProperty SelectedTreeViewItemProperty = DependencyProperty.Register("SelectedTreeViewItem", typeof(MyObject), typeof(MyViewModel), new PropertyMetadata(OnSelectedTreeViewItemChanged));
private static void OnSelectedTreeViewItemChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
(d as MyViewModel).OnSelectedTreeViewItemChanged(e);
}
private void OnSelectedTreeViewItemChanged(DependencyPropertyChangedEventArgs e)
{
//do your stuff here
}
public MyObject SelectedWorkOrderTreeViewItem
{
get { return (MyObject)GetValue(SelectedTreeViewItemProperty); }
set { SetValue(SelectedTreeViewItemProperty, value); }
}
构造函数:
Binding binding = new Binding("SelectedItem")
{
Source = treeView, //name of tree view in xaml
Mode = BindingMode.OneWay
};
BindingOperations.SetBinding(DataContext, MyViewModel.SelectedTreeViewItemProperty, binding);
