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Create Event Handler for TreeViewItem in WPF

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被撕碎了的回忆 2021-01-06 05:22

Im adding items to TreeView control via ItemsSource property and ItemTemplate property to set the template for TreeViewItem. How can i add an event handler to handle selecti

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  • 情歌与酒
    情歌与酒 (楼主)
    2021-01-06 05:49

    There are different ways to Bind of the SelectedItemChanged event of TreeviewItem:

    Method 1: Direct Attaching Event

    The attachment of the event can be done in Xaml

    
        

Private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs e)
{

}



    Or on code Behind
    


    myTreeview.SelectedItemChanged += new RoutedPropertyChangedEventHandler(TreeView_SelectedItemChanged);

private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs e)
{

}



    Method 2 Usage of Extended Class
    


    public class ExtendedTreeView : TreeView
{
    public ExtendedTreeView()
        : base()
    {
        this.SelectedItemChanged += new RoutedPropertyChangedEventHandler(TreeView_SelectedItemChanged);
    }

    void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs 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));
}



    Next just create the Treeview with the new custom class object.
    


    ExtendedTreeView  myTreeview = new ExtendedTreeView();

    


    Method 3 Usage of Behavior
    


    public class BindableSelectedItemBehavior : Behavior
{
    #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;
        }
    }

    


    Next just attach the Treeview to the Behavior 
On Xaml file
    


    
    
        
    


    


    Or on Code Behind
    


    BindableSelectedItemBehavior selectedItemBehavior = new BindableSelectedItemBehavior();
System.Windows.Interactivity.Interaction.GetBehaviors(treeview1).Add(selectedItemBehavior);

    


    Cordially
    
    
    
             
    
                                                        
    
            
            
    
              
                
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