TreeView.TreeNodeCheckChanged TreeView.TreeNodeCheckChanged TreeView.TreeNodeCheckChanged TreeView.TreeNodeCheckChanged Event

Definition

Tritt ein, wenn sich der Zustand eines Kontrollkästchens im TreeView-Steuerelement zwischen Übermittlungen an den Server ändert.Occurs when a check box in the TreeView control changes state between posts to the server.

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

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie das TreeNodeCheckChanged -Ereignis verwendet wird Label , um ein-Steuerelement zu TreeView aktualisieren, wenn die Kontrollkästchen des-Steuer Elements den Zustand zwischen den Beiträgen zum Server ändern.The following code example demonstrates how to use the TreeNodeCheckChanged event to update a Label control when the check boxes of the TreeView control change state between posts to the server.


<%@ 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 LinksTreeView_CheckChanged(Object sender, TreeNodeEventArgs e)
  {

    if(LinksTreeView.CheckedNodes.Count > 0)
    {

      // Clear the message label.
      Message.Text = "You selected: <br /><br />";

      // Iterate through the CheckedNodes collection and display 
      // the selected nodes.
      foreach (TreeNode node in LinksTreeView.CheckedNodes)
      {

        Message.Text += node.Text + "<br />";

      }

    }

    else
    {

      Message.Text = "No items selected.";

    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeView CheckChanged Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeView CheckChanged Example</h3>
    
      <!-- Set the ShowCheckBoxes property declaratively.   -->
      <!-- Because the ShowCheckBoxes property uses a flag  -->
      <!-- enumeration, you can combine multiple values by  -->
      <!-- using the bitwise OR operator. In declarative    -->
      <!-- syntax, this is done using a comma separated     -->
      <!-- list.                                            -->  
      <asp:TreeView id="LinksTreeView"
        ForeColor="Blue"
        ExpandDepth="2"
        ShowCheckBoxes="Parent,Leaf" 
        OnTreeNodeCheckChanged="LinksTreeView_CheckChanged" 
        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:Button id="Submit"
        Text="Select Items"
        runat="server"/>
         
      <br /><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 LinksTreeView_CheckChanged(ByVal sender As Object, ByVal e As TreeNodeEventArgs)

    If LinksTreeView.CheckedNodes.Count > 0 Then

      ' Clear the message label.
      Message.Text = "You selected: <br /><br />"

      ' Iterate through the CheckedNodes collection and display 
      ' the selected nodes.
      Dim node As TreeNode

      For Each node In LinksTreeView.CheckedNodes

        Message.Text &= node.Text & "<br />"

      Next

    Else

      Message.Text = "No items selected."

    End If

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeView CheckChanged Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeView CheckChanged Example</h3>
    
      <!-- Set the ShowCheckBoxes property declaratively.   -->
      <!-- Because the ShowCheckBoxes property uses a flag  -->
      <!-- enumeration, you can combine multiple values by  -->
      <!-- using the bitwise OR operator. In declarative    -->
      <!-- syntax, this is done using a comma separated     -->
      <!-- list.                                            -->  
      <asp:TreeView id="LinksTreeView"
        ForeColor="Blue"
        ExpandDepth="2"
        ShowCheckBoxes="Parent,Leaf" 
        OnTreeNodeCheckChanged="LinksTreeView_CheckChanged" 
        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:Button id="Submit"
        Text="Select Items"
        runat="server"/>
         
      <br /><br />
      
      <asp:Label id="Message"
        runat="server"/>

    </form>
  </body>
</html>

Hinweise

Das TreeNodeCheckChanged -Ereignis wird ausgelöst, wenn ein Kontrollkästchen TreeView im-Steuerelement den Status zwischen den Beiträgen zum Server ändert.The TreeNodeCheckChanged event is raised when a check box in the TreeView control changes state between posts to the server. Dies ermöglicht es Ihnen, eine Ereignis Behandlungsmethode bereitzustellen, die eine benutzerdefinierte Routine ausführt, z. b. das Aktualisieren einer Datenbank oder des angezeigten Inhalts, wenn dieses Ereignis auftritt.This allows you to provide an event-handling method that performs a custom routine, such as updating a database or the displayed content, whenever this event occurs.

Obwohl das Ereignis TreeNodeCheckChanged beim Postback ausgelöst wird, führt das Ändern eines Kontrollkästchens nicht zu einem Postback.Even though the TreeNodeCheckChanged event is fired on post back, changing a check box does not cause a post back.

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