CODEWITHSUNDEEP
wpftreeviewexpand
David Brunelle
David Brunelle

Reputation: 6440

AutoExpand treeview in WPF

Is there a way to automatically expand all nodes from a treeview in WPF? I searched and didn't even find an expand function in the treeview property.

Thanks

Upvotes: 54

Views: 44045

Answers (5)

gmmarcilli
gmmarcilli

Reputation: 53

Another programmatical way to manipulate full expansion of tree items, maybe via c# code, is using the TreeViewItem.ExpandSubTree() command on a root node.

private void ExpandFirstRootNode()
{
   TreeViewControl.Items[0].ExpandSubtree();
}

Upvotes: 0

Darío Andrés Muñoz Prudant
Darío Andrés Muñoz Prudant

Reputation: 71

if you want expand manually you can try

Xaml:

<TreeView x:Name="TreePeople">
    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded" Value="True" />
        </Style>
    </TreeView.ItemContainerStyle>
</TreeView>

c#:

bool Expanded = false; 
// The event subscription method (for a button click)
private void ButtonExpand__Click(object sender, RoutedEventArgs e)
{
    Expanded = !Expanded;
    Style Style = new Style
    {
        TargetType = typeof(TreeViewItem)
    };

    Style.Setters.Add(new Setter(TreeViewItem.IsExpandedProperty, Expanded));
    TreePeople.ItemContainerStyle = Style;
}

Upvotes: 5

Carlo
Carlo

Reputation: 25959

This is what I use:

private void ExpandAllNodes(TreeViewItem rootItem)
{
    foreach (object item in rootItem.Items)
    {
        TreeViewItem treeItem = (TreeViewItem)item;

        if (treeItem != null)
        {
            ExpandAllNodes(treeItem);
            treeItem.IsExpanded = true;
        }
    }
}

In order for it to work you must call this method in a foreach loop for the root node:

// this loop expands all nodes
foreach (object item in myTreeView.Items)
{
    TreeViewItem treeItem = (TreeViewItem)item;

    if (treeItem != null)
    {
        ExpandAllNodes(treeItem);
        treeItem.IsExpanded = true;
    }
}

Upvotes: 5

jwize
jwize

Reputation: 4165

Carlo's answer was better because it opens all levels

This improves upon that example with a little more concise code example.

    private void ExpandAllNodes(TreeViewItem treeItem)
    {
        treeItem.IsExpanded = true;  
        foreach (var childItem in treeItem.Items.OfType<TreeViewItem>())
        {
                ExpandAllNodes(childItem);
        }
    }

Call it by using this line of code 

TreeViewInstance.Items.OfType<TreeViewItem>().ToList().ForEach(ExpandAllNodes);

Upvotes: 2

Anvaka
Anvaka

Reputation: 15823

You can set ItemContainerStyle and use IsExpanded property.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Grid>
      <TreeView>
         <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}">
               <Setter Property="IsExpanded" Value="True"/>
            </Style>
         </TreeView.ItemContainerStyle>
         <TreeViewItem Header="Header 1">
            <TreeViewItem Header="Sub Item 1"/>
         </TreeViewItem>
         <TreeViewItem Header="Header 2">
            <TreeViewItem Header="Sub Item 2"/>
         </TreeViewItem>
      </TreeView>
   </Grid>
</Page>

If you need to do this from code, you can write viewmodel for your tree view items, and bind IsExpanded property to corresponding one from model. For more examples refer to great article from Josh Smith on CodeProject: Simplifying the WPF TreeView by Using the ViewModel Pattern

Upvotes: 89

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