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TreeNodeCollection.Contains Method

Determines whether the specified TreeNode object is in the collection.

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

public bool Contains(
	TreeNode c
)

Parameters

c
Type: System.Web.UI.WebControls.TreeNode

The TreeNode object to find.

Return Value

Type: System.Boolean
true if the specified TreeNode object is contained in the collection; otherwise, false.

Use the Contains method to determine whether a TreeNode object is contained in the TreeNodeCollection. This method is commonly used to test for the existence of a TreeNode object before performing a task, such as adding or removing the node from the collection.

The following example demonstrates how to use the Contains method to determine whether the selected node is in the Nodes collection. Notice that the Nodes property returns a TreeNodeCollection object.

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

    // Determine whether the Nodes collection contains the selected node 
    // and display the appropriate message. 
    if(LinksTreeView.Nodes.Contains(LinksTreeView.SelectedNode))
    {

      Message.Text = "The index of " + LinksTreeView.SelectedNode.Text + 
        " is " +  LinksTreeView.Nodes.IndexOf(LinksTreeView.SelectedNode).ToString();

    }
    else
    {

      Message.Text = "The selected node is not a root node.";

    }

  }

</script>

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

      <h3>TreeNodeCollection Contains Example</h3>

      <h5>Click a root node.</h5>

      <asp:TreeView id="LinksTreeView"
        Font-Names= "Arial"
        ForeColor="Blue"
        OnSelectedNodeChanged="Node_Changed"  
        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="Subtopic 1"/>
                  <asp:TreeNode Text="Subtopic 2"/>

                </asp:TreeNode>
                <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:Label id="Message"
        runat="server"/>

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0
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