CODEWITHSUNDEEP
wpftreeviewc#-4.0
wonea
wonea

Reputation: 4969

Expanded all WPF Treeview Items

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.

Upvotes: 3

Views: 10744

Answers (3)

Kishore Kumar
Kishore Kumar

Reputation: 21863

just add this style 

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

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

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

Upvotes: 14

itsho
itsho

Reputation: 4800

I've found an "Hackish" solution for that. It does not involved with inheritance like the solution suggested here (by Kishore Kumar)

I've added two buttons - "Collapse all" and "Expand All".

Code Behind:

    private void btnCollapseAll_Click(object sender, RoutedEventArgs e)
    {
        foreach (var item in treeView.Items)
        {
            DependencyObject dObject = treeView.ItemContainerGenerator.ContainerFromItem(item);
            CollapseTreeviewItems(((TreeViewItem)dObject));
        }
    }

    private void btnExpandAll_Click(object sender, RoutedEventArgs e)
    {
        foreach (var item in treeView.Items)
        {
            DependencyObject dObject = treeView.ItemContainerGenerator.ContainerFromItem(item);
            ((TreeViewItem)dObject).ExpandSubtree();
        }
    }

    private void CollapseTreeviewItems(TreeViewItem Item)
    {
        Item.IsExpanded = false;

        foreach (var item in Item.Items)
        {
            DependencyObject dObject = treeView.ItemContainerGenerator.ContainerFromItem(item);

            if (dObject != null)
            {
                ((TreeViewItem)dObject).IsExpanded = false;

                if (((TreeViewItem)dObject).HasItems)
                {
                    CollapseTreeviewItems(((TreeViewItem)dObject));
                }
            }
        }
    }

My solution is based on this

Upvotes: 4

Nir
Nir

Reputation: 29584

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

Upvotes: 0

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