Partilhar via

TreeView.TreeNodeExpanded Evento

  • Referência

Definição

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Ocorre quando um nó é expandido no controle TreeView.

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

Tipo de evento

TreeNodeEventHandler

Exemplos

O exemplo de código a seguir demonstra como usar o TreeNodeExpanded evento para atualizar o conteúdo de um Label controle quando o usuário expande um nó no TreeView controle.


<%@ 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>

Comentários

O TreeNodeExpanded evento é gerado quando um nó é expandido no TreeView controle . Isso permite que você forneça um método de manipulação de eventos que executa uma rotina personalizada sempre que esse evento ocorre.

Observação

Se a SelectAction propriedade de um nó estiver definida TreeNodeSelectAction.Expand como ou TreeNodeSelectAction.SelectExpand, o TreeNodeExpanded evento também será gerado quando esse nó for clicado no TreeView controle .

Para obter mais informações sobre como lidar com eventos, consulte Manipulando e levantando eventos.

Aplica-se a

Confira também