TreeView.TreeNodeCollapsed Event
Occurs when a node is collapsed in the TreeView control.
Assembly: System.Web (in System.Web.dll)
The TreeNodeCollapsed event is raised when a node is collapsed in the TreeView control. This allows you to provide an event-handling method that performs a custom routine whenever this event occurs.
For more information about handling events, see Consuming Events.
The following code example demonstrates how to use the TreeNodeCollapsed event to update the content of a Label control when the user collapses a node in the TreeView control.
<%@ 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_Expand(ByVal sender As Object, ByVal e As TreeNodeEventArgs) Message.Text = "You expanded the " & e.Node.Text & " node." End Sub Sub Node_Collapse(ByVal sender As Object, ByVal e As TreeNodeEventArgs) Message.Text = "You collapsed the " & e.Node.Text & " node." End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>TreeView TreeNodeExpand and TreeNodeCollapse Example</title> </head> <body> <form id="form1" runat="server"> <h3>TreeView TreeNodeExpand and TreeNodeCollapse Example</h3> <asp:TreeView id="BookTreeView" ExpandDepth="1" OnTreeNodeExpanded="Node_Expand" OnTreeNodeCollapsed="Node_Collapse" runat="server"> <Nodes> <asp:TreeNode Value="Chapter 1" Text="Chapter 1"> <asp:TreeNode Value="Section 1" Text="Section 1"> <asp:TreeNode Value="Paragraph 1" Text="Paragraph 1"> </asp:TreeNode> </asp:TreeNode> <asp:TreeNode Value="Section 2" Text="Section 2"> </asp:TreeNode> </asp:TreeNode> </Nodes> </asp:TreeView> <br /> <asp:Label id="Message" runat="server"/> </form> </body> </html>
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.