TreeViewNode.Expanded Property

Gets or sets whether the node is expanded.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v18.2.dll

Declaration

C#

[DefaultValue(false)]
public virtual bool Expanded { get; set; }

VB.NET

<DefaultValue(False)>
Public Overridable Property Expanded As Boolean

Property Value

Type	Default	Description
Boolean	**false**	true if the node is expanded; false if the node is collapsed.

Remarks

Use the Expanded property to expand or collapse a node.

Note that changing the Expanded property in code doesn’t invoke the ASPxTreeView.ExpandedChanging and the ASPxTreeView.ExpandedChanged events.

To expand/collapse all nodes, use the following methods:

Server method	Client method	Describtion
ASPxTreeView.ExpandAll	ASPxClientTreeView.ExpandAll	Expands all nodes
ASPxTreeView.CollapseAll	ASPxClientTreeView.CollapseAll	Collapses all nodes
ASPxTreeView.ExpandToDepth	None	Expands all nodes to the specified depth

Example

The sample code below represents an ASPxTreeView.ExpandedChanging event handler. The event handler prevents collapsing nodes if it has selected children in any generation.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-prevent-parent-node-collapsing-e2439

Default.aspx.cs

using DevExpress.Web.ASPxTreeView;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void ASPxTreeView1_ExpandedChanging(object source, DevExpress.Web.ASPxTreeView.TreeViewNodeCancelEventArgs e) {
        if ((e.Node.Expanded) && (ASPxTreeView1.SelectedNode != null)) {
            TreeViewNode  node = ASPxTreeView1.SelectedNode.Parent;
            while (node != null) {
                if (e.Node == node) {
                    e.Cancel = true;
                    break;
                }
                node = node.Parent;
            }
        }
    }
}

Default.aspx (C#)

<dx:ASPxTreeView ID="ASPxTreeView1" runat="server" DataSourceID="XmlDataSource1" AutoPostBack="True" AllowSelectNode="True" OnExpandedChanging="ASPxTreeView1_ExpandedChanging">
</dx:ASPxTreeView>
<asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/MenuTabbedMenu.xml"
    XPath="/mainmenu/item"></asp:XmlDataSource>

Default.aspx (VB.NET)

<dx:ASPxTreeView ID="ASPxTreeView1" runat="server" DataSourceID="XmlDataSource1" AutoPostBack="True" AllowSelectNode="True" OnExpandedChanging="ASPxTreeView1_ExpandedChanging">
 </dx:ASPxTreeView>
 <asp:XmlDataSource ID="XmlDataSource1" runat="server" DataFile="~/App_Data/MenuTabbedMenu.xml"
     XPath="/mainmenu/item"></asp:XmlDataSource>

Default.aspx.vb

Imports DevExpress.Web.ASPxTreeView

Partial Public Class _Default
    Inherits System.Web.UI.Page
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    End Sub
    Protected Sub ASPxTreeView1_ExpandedChanging(ByVal source As Object, ByVal e As DevExpress.Web.ASPxTreeView.TreeViewNodeCancelEventArgs)
        e.Node.Expanded = True
        If e.Node.Expanded AndAlso (ASPxTreeView1.SelectedNode IsNot Nothing) Then
            Dim node As TreeViewNode = ASPxTreeView1.SelectedNode.Parent
            Do While node IsNot Nothing
                If e.Node Is node Then
                    e.Cancel = True
                    Exit Do
                End If
                node = node.Parent
            Loop
        End If
    End Sub
End Class

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the Expanded property.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-implement-sidebar-navigation-shown-in-devexpress-demos-t598380/CS/AdaptiveSlideNavigation/UserControls/Navigation.ascx.cs#L20

NavigationTreeView.ExpandToNode(node);
node.Expanded = true;
while(node != null) {

VB.NET

how-to-implement-sidebar-navigation-shown-in-devexpress-demos-t598380/VB/AdaptiveSlideNavigation/UserControls/Navigation.ascx.vb#L24

NavigationTreeView.ExpandToNode(node)
node.Expanded = True
Do While node IsNot Nothing