TreeView.Nodes Proprietà

  • Riferimento

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Ottiene un insieme di oggetti TreeNode che rappresentano i nodi radice nel controllo TreeView.

public:
 property System::Web::UI::WebControls::TreeNodeCollection ^ Nodes { System::Web::UI::WebControls::TreeNodeCollection ^ get(); };
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public System.Web.UI.WebControls.TreeNodeCollection Nodes { get; }
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.Nodes : System.Web.UI.WebControls.TreeNodeCollection
Public ReadOnly Property Nodes As TreeNodeCollection

Valore della proprietà

TreeNodeCollection

Oggetto TreeNodeCollection che contiene i nodi radice nel controllo TreeView.

Attributi
PersistenceModeAttribute

Esempio

Nell'esempio di codice seguente viene illustrato come usare la proprietà per attraversare l'albero Nodes .


<%@ 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 Page_Load(Object sender, EventArgs e)
  {

    // If the TreeView control contains any root nodes, perform a
    // preorder traversal of the tree and display the text of each node.
    if(LinksTreeView.Nodes.Count > 0)
    {

      // Iterate through the root nodes in the Nodes property.
      for(int i=0; i<LinksTreeView.Nodes.Count; i++)
      {

        // Display the nodes.
        DisplayChildNodeText(LinksTreeView.Nodes[i]);

      }
      
    }
    else
    {
    
      Message.Text = "The TreeView control does not have any nodes.";
    
    }

  }

  void DisplayChildNodeText(TreeNode node)
  {
  
    // Display the node's text value.
    Message.Text += node.Text + "<br />";

    // Iterate through the child nodes of the parent node passed into
    // this method and display their values.
    for(int i=0; i<node.ChildNodes.Count; i++)
    {

      // Recursively call the DisplayChildNodeText method to
      // traverse the tree and display all the child nodes.
      DisplayChildNodeText(node.ChildNodes[i]);

    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeNodeCollection Count Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeNodeCollection Count Example</h3>
    
      <asp:TreeView id="LinksTreeView"
        Font-Names= "Arial"
        ForeColor="Blue"
        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"
            Expanded="true">
             
            <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="Subtopic 1"/>
                  <asp:TreeNode Text="Subtopic 2"/>
                
                </asp:TreeNode>
                <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>


<%@ 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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    ' If the TreeView control contains any root nodes, perform a
    ' preorder traversal of the tree and display the text of each node.
    If LinksTreeView.Nodes.Count > 0 Then

      ' Iterate through the root nodes in the Nodes property.
      Dim i As Integer

      For i = 0 To LinksTreeView.Nodes.Count - 1

        ' Display the nodes.
        DisplayChildNodeText(LinksTreeView.Nodes(i))

      Next i

    Else

      Message.Text = "The TreeView control does not have any nodes."

    End If

  End Sub

  Sub DisplayChildNodeText(ByVal node As TreeNode)

    ' Display the node's text value.
    Message.Text &= node.Text & "<br />"

    ' Iterate through the child nodes of the parent node passed into
    ' this method and display their values.
    Dim i As Integer

    For i = 0 To node.ChildNodes.Count - 1

      ' Recursively call the DisplayChildNodeText method to
      ' traverse the tree and display all the child nodes.
      DisplayChildNodeText(node.ChildNodes(i))

    Next i

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeNodeCollection Count Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeNodeCollection Count Example</h3>
    
      <asp:TreeView id="LinksTreeView"
        Font-Names= "Arial"
        ForeColor="Blue"
        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"
            Expanded="true">
             
            <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="Subtopic 1"/>
                  <asp:TreeNode Text="Subtopic 2"/>
                
                </asp:TreeNode>
                <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>

Commenti

Utilizzare la Nodes proprietà per ottenere un TreeNodeCollection oggetto contenente tutti i nodi radice nell'albero. Questa raccolta viene comunemente usata per eseguire rapidamente l'iterazione di tutti i nodi radice o per accedere a un nodo radice specifico nell'albero.

Nota

Una struttura ad albero tipica ha un solo nodo radice; tuttavia, è possibile aggiungere più nodi radice al TreeView controllo.

La Nodes proprietà può essere usata anche per gestire i nodi radice nell'albero a livello di codice. È possibile aggiungere, inserire, rimuovere e recuperare TreeNode oggetti dalla raccolta. Tutti gli aggiornamenti della raccolta vengono riflessi automaticamente nel controllo dopo il TreeView round trip successivo al server.

Per accedere ai nodi figlio di un nodo radice, usare la ChildNodes proprietà del nodo. Utilizzare la ChildNodes proprietà di ogni nodo a livello padre successivo per spostarsi verso il basso i livelli di nodo.

Si applica a

Vedi anche