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TreeNode.ExpandAll Method

Expands the current node and all its child nodes.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

public void ExpandAll()

Use the ExpandAll method to conveniently expand the current node and all its child nodes.

NoteNote

As an alternative, you can also set the Expanded property of the current node and each of its child nodes to true.

To expand only the current node, consider using the Expand method.

ExpandAll will expand all the nodes in the entire tree.

The following code example demonstrates how to use the ExpandAll method to programmatically expand a node and all its child nodes in the TreeView control. For this example to work correctly, you must copy the sample XML data below to a file named Book.xml.


<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

  void Data_Bound(Object sender, TreeNodeEventArgs e)
  {

    // Determine the depth of a node as it is bound to data.
    // If the depth is 1, expand the node.
    if(e.Node.Depth == 1)
    {

      // Expand the node using the ExpandAll method.
      e.Node.ExpandAll();

    }
    else
    {

      // Collapse the node using the CollapseAll method.
      e.Node.CollapseAll();

    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeNode ExpandAll and CollapseAll Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>TreeNode ExpandAll and CollapseAll Example</h3>

      <h5>Expand the root node. Notice that the child nodes are already expanded.</h5>

      <asp:TreeView id="BookTreeView" 
         DataSourceID="BookXmlDataSource"
         OnTreeNodeDataBound="Data_Bound"
         runat="server">

        <DataBindings>
          <asp:TreeNodeBinding DataMember="Book" TextField="Title"/>
          <asp:TreeNodeBinding DataMember="Chapter" TextField="Heading"/>
          <asp:TreeNodeBinding DataMember="Section" TextField="Heading"/>
        </DataBindings>

      </asp:TreeView>

      <asp:XmlDataSource id="BookXmlDataSource"  
         DataFile="Book.xml"
         runat="server">
      </asp:XmlDataSource>

    </form>
  </body>
</html>

The following code is sample XML data for the previous example.

<Book Title="Book Title">
    <Chapter Heading="Chapter 1">
        <Section Heading="Section 1">
        </Section>
        <Section Heading="Section 2">
        </Section>
    </Chapter>
    <Chapter Heading="Chapter 2">
        <Section Heading="Section 1">
        </Section>
    </Chapter>
</Book>

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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