TreeView.SelectedNodeChanged Event
Occurs when a node is selected in the TreeView control.
Assembly: System.Web (in System.Web.dll)
The SelectedNodeChanged event is raised when a node is selected in the TreeView control. This allows you to provide an event-handling method that performs a custom routine, such as updating the displayed content, whenever this event occurs.
You can optionally set the SelectAction property for a node to specify which event is raised when that node is selected. The following table lists the available options.
Selection action | Description |
|---|---|
Toggles the node between expanded and collapsed. Raises the TreeNodeExpanded or TreeNodeCollapsed event, as appropriate. | |
Raises no events when a node is selected. | |
Raises the SelectedNodeChanged event when a node is selected. | |
Raises both the SelectedNodeChanged and TreeNodeExpanded events when a node is selected. Nodes are only expanded, never collapsed. |
Note |
|---|
The HoverNodeStyle is not rendered for a node with its SelectAction property set to TreeNodeSelectAction.None. |
The SelectedNodeChanged event is fired only on post back when a user clicks a node. The event is not fired if the SelectedNode property is changed programmatically.
For more information about handling events, see NIB: Consuming Events.
The following code example demonstrates how to use the SelectedNodeChanged event to update a Label control when a node is selected in the 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 Select_Change(Object sender, EventArgs e) { Message.Text = "You selected: " + LinksTreeView.SelectedNode.Text; } </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>TreeView SelectedNodeStyle Example</title> </head> <body> <form id="form1" runat="server"> <h3>TreeView SelectedNodeStyle Example</h3> <asp:TreeView id="LinksTreeView" Font-Names= "Arial" ForeColor="Blue" SelectedNodeStyle-ForeColor="Green" SelectedNodeStyle-VerticalPadding="0" OnSelectedNodeChanged="Select_Change" 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" SelectAction="None"> <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> <br /><br /> <asp:Label id="Message" runat="server"/> </form> </body> </html>
Available since 2.0
