How to programmatically select an item in a WPF TreeView?

It's a real pain for some strange reason, you have to use ContainerFromItem to get the container, then invoke the select method.

//  selectedItemObject is not a TreeViewItem, but an item from the collection that 
//  populated the TreeView.

var tvi = treeView.ItemContainerGenerator.ContainerFromItem(selectedItemObject) 
          as TreeViewItem;

if (tvi != null)
{
    tvi.IsSelected = true;
}

There once was a blog entry on how to do it here, but the link is dead now.

You need to get the TreeViewItem and then set IsSelected to true.

I've succeeded with this code:

public static TreeViewItem FindTviFromObjectRecursive(ItemsControl ic, object o) {
  //Search for the object model in first level children (recursively)
  TreeViewItem tvi = ic.ItemContainerGenerator.ContainerFromItem(o) as TreeViewItem;
  if (tvi != null) return tvi;
  //Loop through user object models
  foreach (object i in ic.Items) {
    //Get the TreeViewItem associated with the iterated object model
    TreeViewItem tvi2 = ic.ItemContainerGenerator.ContainerFromItem(i) as TreeViewItem;
    tvi = FindTviFromObjectRecursive(tvi2, o);
    if (tvi != null) return tvi;
  }
  return null;
}

Usage:

var tvi = FindTviFromObjectRecursive(TheTreeView, TheModel);
if (tvi != null) tvi.IsSelected = true;

For those who are still looking for the right solution to this problem here is the one below. I found this one in the comments to the Code Project article “WPF TreeView Selection” http://www.codeproject.com/KB/WPF/TreeView_SelectionWPF.aspx by DaWanderer. It was posted by Kenrae on Nov 25 2008. This worked great for me. Thanks Kenrae!

Here is his post:

Instead of walking the tree, have your own data object have the IsSelected property (and I recommend the IsExpanded property too). Define a style for the TreeViewItems of the tree using the ItemContainerStyle property on the TreeView that binds those properties from the TreeViewItem to your data objects. Something like this:

<Style x:Key="LibraryTreeViewItemStyle"
               TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded"
                        Value="{Binding IsExpanded, Mode=TwoWay}" />
            <Setter Property="IsSelected"
                        Value="{Binding IsSelected, Mode=TwoWay}" />
            <Setter Property="FontWeight"
                        Value="Normal" />
            <Style.Triggers>
                  <Trigger Property="IsSelected"
                              Value="True">
                        <Setter Property="FontWeight"
                                    Value="Bold" />
                  </Trigger>
            </Style.Triggers>
      </Style>

<TreeView ItemsSource="{Binding Path=YourCollection}"
               ItemContainerStyle="{StaticResource LibraryTreeViewItemStyle}"
               ItemTemplate={StaticResource YourHierarchicalDataTemplate}/>