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TreeNode.ToggleExpandState Method

Alternates between the expanded and collapsed state of the node.

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

public void ToggleExpandState()

Use the ToggleExpandState method to alternate between an expanded and a collapsed state for the node. For example, if the node is collapsed, calling the ToggleExpandState method expands the node, and vice versa.

NoteNote

As an alternative, you can set the Expanded property directly.

The following code example demonstrates how to use the ToggleExpandState method to alternate between an expanded and a collapsed state for the root node of a TreeView control.


<%@ 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 Check_Changed(Object sender, EventArgs e)
  {

    // Alternate the state of the root node. The root node
    // is the first element (index 0) of the Nodes collection.
    LinksTreeView.Nodes[0].ToggleExpandState();

  }

</script>

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

      <h3>TreeNode ToggleExpandState Example</h3>

      <asp:TreeView id="LinksTreeView"
        Font-Names= "Arial"
        ForeColor="Blue"
        runat="server">

        <LevelStyles>

          <asp:TreeNodeStyle ChildNodesPadding="10" 
            Font-Bold="true" 
            Font-Size="12pt" 
            ForeColor="DarkGreen"/>
          <asp:TreeNodeStyle ChildNodesPadding="5" 
            Font-Bold="true" 
            Font-Size="10pt"/>
          <asp:TreeNodeStyle ChildNodesPadding="5" 
            Font-UnderLine="true" 
            Font-Size="10pt"/>
          <asp:TreeNodeStyle ChildNodesPadding="10" 
            Font-Size="8pt"/>

        </LevelStyles>

        <Nodes>

          <asp:TreeNode Text="Table of Contents"
            Expanded="true">

            <asp:TreeNode Text="Chapter One">

              <asp:TreeNode Text="Section 1.0">

                <asp:TreeNode Text="Topic 1.0.1"/>
                <asp:TreeNode Text="Topic 1.0.2"/>
                <asp:TreeNode Text="Topic 1.0.3"/>

              </asp:TreeNode>

              <asp:TreeNode Text="Section 1.1">

                <asp:TreeNode Text="Topic 1.1.1"/>
                <asp:TreeNode Text="Topic 1.1.2"/>
                <asp:TreeNode Text="Topic 1.1.3"/>
                <asp:TreeNode Text="Topic 1.1.4"/>

              </asp:TreeNode>

            </asp:TreeNode>

            <asp:TreeNode Text="Chapter Two">

              <asp:TreeNode Text="Section 2.0">

                <asp:TreeNode Text="Topic 2.0.1"/>
                <asp:TreeNode Text="Topic 2.0.2"/>

              </asp:TreeNode>

            </asp:TreeNode>

          </asp:TreeNode>

          <asp:TreeNode Text="Appendix A" />
          <asp:TreeNode Text="Appendix B" />
          <asp:TreeNode Text="Appendix C" />

        </Nodes>

      </asp:TreeView> 

      <hr />

      <asp:CheckBox id="ToggleExpandStateCheckBox"
        Text="Expand Table of Contents node"
        Checked="true" 
        AutoPostBack="true"
        OnCheckedChanged="Check_Changed"
        runat="server"/>

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0
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