Expanded all WPF Treeview Items

Question

I'm trying to iterate through my Treeview, expanding all nodes however it runs into an InvalidCastException when ran;

Unable to cast object of type 'System.Data.DataRowView' to type 'System.Windows.Controls.TreeViewItem'.

My Code;

foreach (TreeViewItem treeitem in thetreeView.Items)
{
   treeitem.IsExpanded = true;
}

Any ideas? I want to fire this from a button.

Answer 1

just add this style

<Style TargetType="TreeViewItem"> 
    <Setter Property="IsExpanded" Value="True" /> 
</Style> 

for code please go through this link may be this can help u

http://bea.stollnitz.com/blog/?p=55

Answer 2

Bag of tricks has a demo called "TreeView Expand" that has a tree view with expand all and collapse all buttons (and some more)