TreeNodeCollection.Contains(TreeNode) Method
Definition
Important
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Determines whether the specified TreeNode object is in the collection.
public:
bool Contains(System::Web::UI::WebControls::TreeNode ^ c);public bool Contains (System.Web.UI.WebControls.TreeNode c);member this.Contains : System.Web.UI.WebControls.TreeNode -> boolPublic Function Contains (c As TreeNode) As BooleanParameters
Returns
true if the specified TreeNode object is contained in the collection; otherwise, false.
Examples
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>
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub Node_Changed(ByVal sender As Object, ByVal e As EventArgs)
' Determine whether the Nodes collection contains the selected node
' and display the appropriate message.
If LinksTreeView.Nodes.Contains(LinksTreeView.SelectedNode) Then
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."
End If
End Sub
</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>
Remarks
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.
Applies to
See also
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