TreeView.TreeNodeCollapsed Evento

Definizione

Si verifica quando si comprime un nodo nel controllo TreeView.Occurs when a node is collapsed in the TreeView control.

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

Esempi

Nell'esempio di codice riportato di seguito viene illustrato TreeNodeCollapsed come utilizzare l'evento per aggiornare il Label contenuto di un controllo quando l'utente comprime un nodo TreeView nel controllo.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="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>

Commenti

L' TreeNodeCollapsed evento viene generato quando un nodo viene compresso TreeView nel controllo.The TreeNodeCollapsed event is raised when a node is collapsed in the TreeView control. In questo modo è possibile fornire un metodo di gestione degli eventi che esegua una routine personalizzata ogni volta che si verifica questo evento.This allows you to provide an event-handling method that performs a custom routine whenever this event occurs.

Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.For more information about how to handle events, see Handling and Raising Events.

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