TreeView.TreeNodeExpanded Ereignis

Definition

Wird ausgelöst, wenn ein Knoten im TreeView-Steuerelement erweitert wird.Occurs when a node is expanded in the TreeView control.

public:
 event System::Web::UI::WebControls::TreeNodeEventHandler ^ TreeNodeExpanded;
public event System.Web.UI.WebControls.TreeNodeEventHandler TreeNodeExpanded;
member this.TreeNodeExpanded : System.Web.UI.WebControls.TreeNodeEventHandler 
Public Custom Event TreeNodeExpanded As TreeNodeEventHandler 

Ereignistyp

TreeNodeEventHandler

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie das-Ereignis verwendet wird TreeNodeExpanded , um den Inhalt eines-Steuer Elements zu aktualisieren, Label Wenn der Benutzer einen Knoten im-Steuerelement erweitert TreeView .The following code example demonstrates how to use the TreeNodeExpanded event to update the content of a Label control when the user expands a node 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 Node_Expand(Object sender, TreeNodeEventArgs e)
  {

    Message.Text = "You expanded the " + e.Node.Text + " node.";

  }

  void Node_Collapse(Object sender, TreeNodeEventArgs e)
  {

    Message.Text = "You collapsed the " + e.Node.Text + " node.";

  }

</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>


<%@ 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>

Hinweise

Das- TreeNodeExpanded Ereignis wird ausgelöst, wenn ein Knoten im-Steuerelement erweitert wird TreeView .The TreeNodeExpanded event is raised when a node is expanded in the TreeView control. Dies ermöglicht es Ihnen, eine Ereignis Behandlungsmethode bereitzustellen, die immer dann eine benutzerdefinierte Routine ausführt, wenn dieses Ereignis auftritt.This allows you to provide an event-handling method that performs a custom routine whenever this event occurs.

Hinweis

Wenn die- SelectAction Eigenschaft eines Knotens auf oder festgelegt ist TreeNodeSelectAction.Expand TreeNodeSelectAction.SelectExpand , wird das- TreeNodeExpanded Ereignis auch ausgelöst, wenn auf diesen Knoten im-Steuerelement geklickt wird TreeView .If the SelectAction property for a node is set to TreeNodeSelectAction.Expand or TreeNodeSelectAction.SelectExpand, the TreeNodeExpanded event is also raised when that node is clicked in the TreeView control.

Weitere Informationen zum Behandeln von Ereignissen finden Sie unter behandeln und Auslösen von Ereignissen.For more information about how to handle events, see Handling and Raising Events.

Gilt für:

Siehe auch