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;
}

当前回答

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>

其他回答

我找到了一个解决办法。它可以移动混乱,这样MVVM就可以工作了。

首先添加这个类:

public class ExtendedTreeView : TreeView
{
    public ExtendedTreeView()
        : base()
    {
        this.SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(___ICH);
    }

    void ___ICH(object sender, RoutedPropertyChangedEventArgs<object> e)
    {
        if (SelectedItem != null)
        {
            SetValue(SelectedItem_Property, SelectedItem);
        }
    }

    public object SelectedItem_
    {
        get { return (object)GetValue(SelectedItem_Property); }
        set { SetValue(SelectedItem_Property, value); }
    }
    public static readonly DependencyProperty SelectedItem_Property = DependencyProperty.Register("SelectedItem_", typeof(object), typeof(ExtendedTreeView), new UIPropertyMetadata(null));
}

并添加到你的xaml:

 <local:ExtendedTreeView ItemsSource="{Binding Items}" SelectedItem_="{Binding Item, Mode=TwoWay}">
 .....
 </local:ExtendedTreeView>

你也可以使用TreeViewItem。IsSelected财产

它的答案比OP期待的要多一点…但我希望它至少能帮助到一些人。

如果你想在SelectedItem改变时执行ICommand,你可以在事件上绑定一个命令,不再需要在ViewModel中使用属性SelectedItem。

这样做:

1-添加System.Windows.Interactivity引用

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

2-将命令绑定到事件SelectedItemChanged

<TreeView x:Name="myTreeView" Margin="1"
            ItemsSource="{Binding Directories}">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="SelectedItemChanged">
            <i:InvokeCommandAction Command="{Binding SomeCommand}"
                                   CommandParameter="
                                            {Binding ElementName=myTreeView
                                             ,Path=SelectedItem}"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>
    <TreeView.ItemTemplate>
           <!-- ... -->
    </TreeView.ItemTemplate>
</TreeView>

在学习了一天的互联网后,我找到了自己的解决方案,在一个普通的WPF/ c#环境中创建一个普通的树视图后选择一个项目

private void BuildSortTree(int sel)
        {
            MergeSort.Items.Clear();
            TreeViewItem itTemp = new TreeViewItem();
            itTemp.Header = SortList[0];
            MergeSort.Items.Add(itTemp);
            TreeViewItem prev;
            itTemp.IsExpanded = true;
            if (0 == sel) itTemp.IsSelected= true;
            prev = itTemp;
            for(int i = 1; i<SortList.Count; i++)
            {

                TreeViewItem itTempNEW = new TreeViewItem();
                itTempNEW.Header = SortList[i];
                prev.Items.Add(itTempNEW);
                itTempNEW.IsExpanded = true;
                if (i == sel) itTempNEW.IsSelected = true;
                prev = itTempNEW ;
            }
        }

(让我们都同意,TreeView在这个问题上显然是行不通的。绑定到SelectedItem是显而易见的。叹息)

我需要解决方案来正确地与TreeViewItem的IsSelected属性交互,所以这是我是如何做到的:

// the Type CustomThing needs to implement IsSelected with notification
// for this to work.
public class CustomTreeView : TreeView
{
    public CustomThing SelectedCustomThing
    {
        get
        {
            return (CustomThing)GetValue(SelectedNode_Property);
        }
        set
        {
            SetValue(SelectedNode_Property, value);
            if(value != null) value.IsSelected = true;
        }
    }

    public static DependencyProperty SelectedNode_Property =
        DependencyProperty.Register(
            "SelectedCustomThing",
            typeof(CustomThing),
            typeof(CustomTreeView),
            new FrameworkPropertyMetadata(
                null,
                FrameworkPropertyMetadataOptions.None,
                SelectedNodeChanged));

    public CustomTreeView(): base()
    {
        this.SelectedItemChanged += new RoutedPropertyChangedEventHandler<object>(SelectedItemChanged_CustomHandler);
    }

    void SelectedItemChanged_CustomHandler(object sender, RoutedPropertyChangedEventArgs<object> e)
    {
        SetValue(SelectedNode_Property, SelectedItem);
    }

    private static void SelectedNodeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var treeView = d as CustomTreeView;
        var newNode = e.NewValue as CustomThing;

        treeView.SelectedCustomThing = (CustomThing)e.NewValue;
    }
}

用这个XAML:

<local:CustonTreeView ItemsSource="{Binding TreeRoot}" 
    SelectedCustomThing="{Binding SelectedNode,Mode=TwoWay}">
    <TreeView.ItemContainerStyle>
        <Style TargetType="TreeViewItem">
            <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
        </Style>
    </TreeView.ItemContainerStyle>
</local:CustonTreeView>