select a new treeViewItem after insertion in WPF

Question

in WPF ,I have a treeview that is bind to a hierarchical list. when I want to insert a new node to the tree and edit the name of that new node (like folder treeview in Windows), I can not select new node programmatically. I can select parent node or even I can select the new node after insertion. but I want to select new node while I am inserting new node.

<HierarchicalDataTemplate x:Key="hierarchi" ItemsSource="{Binding Path=Items}" >
        <StackPanel Orientation="Horizontal" Margin="2" MouseLeftButtonDown="Item_MouseLeftButtonDown" Tag="{Binding}" >
            <Image  Name="itemImage" Source="{Binding Path=Image}"  Height="16" Width="16"/>
            <TextBlock Name="textBlockName" VerticalAlignment="Center" Text="{Binding Path=Name}" FontFamily="Tahoma" FontSize="12" />
            <TextBox Name="textBoxName" VerticalAlignment="Center" Text="{Binding Path=Name,Mode=TwoWay}" Visibility="Hidden"  FontFamily="Tahoma" FontSize="12" KeyDown="textBoxName_KeyDown" LostFocus="textBoxName_LostFocus"/>
        </StackPanel>          
</HierarchicalDataTemplate>

my data model is something like this:

public class Model:INotifyPropertyChanged
    {
        //other methods and properties are removed.


        private string name;
        public string Name
        {
            get { return name; }
            set { name = value;
            OnPropertyChange("Name");
            }
        }

        private ObservableCollection items = null;
        public ObservableCollection Items
        {
            get { return items; }
            set { items = value;
            OnPropertyChange("Items");
            }
        }
}

here is the code of adding a node :

private void buttonNew_Click(object sender, RoutedEventArgs e)
    {
        if (treeView.SelectedItem is Model)
        {
            Model parent= (Model)treeView.SelectedItem;

            Model newItem = new Model();
            newItem.Parent = post;
            newItem.Name = "New";
            newItem.ParentID = parent.ID;
            parent.Items.Add(newItem);


            TreeViewItem item = GetTreeViewItem(newItem);

            //problem is here, item is null.
            if(item!=null)
                item.IsSelected = true;
                        }
    }
private TreeViewItem GetTreeViewItem(Model node)
    {
// a recursive method for going to root of the tree and coming back

        if (node.Parent == null)
        {
            DependencyObject dObject = treeView.ItemContainerGenerator.ContainerFromItem(node);
            return (TreeViewItem)dObject;
        }
        TreeViewItem parentItem = GetTreeViewItem(node.Parent);
        if (parentItem == null)
            return null;
        DependencyObject Dependency = parentItem.ItemContainerGenerator.ContainerFromItem(node);
        return (TreeViewItem)Dependency;

    }

I am sure I have to update or render treeview datasource, but I don't know how.

Christian Christian · Accepted Answer · 2013-06-11T18:59:33

You need to define a IsSelected property in your viewmodel and call OnPropertyChanged when the property is set. To link IsSelected to your TreeViewItem define an ItemContainerStyle, for instance in your Resources or directly in your TreeView.

  <TreeView.ItemContainerStyle>
    <Style TargetType="{x:Type TreeViewItem}">
      <Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}" />
      <Style.Triggers>
        <Trigger Property="IsSelected" Value="True">
          <Setter Property="FontWeight" Value="Bold" />
        </Trigger>
      </Style.Triggers>
    </Style>
  </TreeView.ItemContainerStyle>

Once you accomplished with that, just set _model.IsSelected = true

select a new treeViewItem after insertion in WPF

1 Answers