TreeView Construtor
Definição
Importante
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Inicializa uma nova instância da classe TreeView.
public:
TreeView();public TreeView ();Public Sub New ()Exemplos
Esta seção contém dois exemplos de código. O primeiro exemplo de código demonstra como usar o TreeView construtor para adicionar um TreeView controle a uma página dinamicamente. O segundo exemplo de código fornece dados XML de exemplo para o primeiro exemplo de código.
O exemplo de código a seguir demonstra como usar o TreeView construtor para adicionar um TreeView controle a uma página dinamicamente. Para que este exemplo funcione corretamente, você deve copiar os dados XML de exemplo fornecidos após este exemplo de código para um arquivo chamado Book.xml.
<%@ 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)
{
// Create a new TreeView control.
TreeView NewTree = new TreeView();
// Set the properties of the TreeView control.
NewTree.ID = "BookTreeView";
NewTree.DataSourceID = "BookXmlDataSource";
// Create the tree node binding relationship.
// Create the root node binding.
TreeNodeBinding RootBinding = new TreeNodeBinding();
RootBinding.DataMember = "Book";
RootBinding.TextField = "Title";
// Create the parent node binding.
TreeNodeBinding ParentBinding = new TreeNodeBinding();
ParentBinding.DataMember = "Chapter";
ParentBinding.TextField = "Heading";
// Create the leaf node binding.
TreeNodeBinding LeafBinding = new TreeNodeBinding();
LeafBinding.DataMember = "Section";
LeafBinding.TextField = "Heading";
// Add bindings to the DataBindings collection.
NewTree.DataBindings.Add(RootBinding);
NewTree.DataBindings.Add(ParentBinding);
NewTree.DataBindings.Add(LeafBinding);
// Manually register the event handler for the SelectedNodeChanged event.
NewTree.SelectedNodeChanged += new EventHandler(this.Node_Change);
// Add the TreeView control to the Controls collection of the PlaceHolder control.
ControlPlaceHolder.Controls.Add(NewTree);
}
void Node_Change(Object sender, EventArgs e)
{
// Retrieve the TreeView control from the Controls collection of the PlaceHolder control.
TreeView LocalTree = (TreeView)ControlPlaceHolder.FindControl("BookTreeView");
// Display the selected node.
Message.Text = "You selected: " + LocalTree.SelectedNode.Text;
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>TreeView Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeView Constructor Example</h3>
<asp:PlaceHolder id="ControlPlaceHolder" runat="server">
</asp:PlaceHolder>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Book.xml"
runat="server">
</asp:XmlDataSource>
<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)
' Create a new TreeView control.
Dim NewTree As New TreeView
' Set the properties of the TreeView control.
NewTree.ID = "BookTreeView"
NewTree.DataSourceID = "BookXmlDataSource"
' Create the tree node binding relationship.
' Create the root node binding.
Dim RootBinding As New TreeNodeBinding
RootBinding.DataMember = "Book"
RootBinding.TextField = "Title"
' Create the parent node binding.
Dim ParentBinding As New TreeNodeBinding
ParentBinding.DataMember = "Chapter"
ParentBinding.TextField = "Heading"
' Create the leaf node binding.
Dim LeafBinding As New TreeNodeBinding
LeafBinding.DataMember = "Section"
LeafBinding.TextField = "Heading"
' Add bindings to the DataBindings collection.
NewTree.DataBindings.Add(RootBinding)
NewTree.DataBindings.Add(ParentBinding)
NewTree.DataBindings.Add(LeafBinding)
' Manually register the event handler for the SelectedNodeChanged event.
AddHandler NewTree.SelectedNodeChanged, AddressOf Node_Change
' Add the TreeView control to the Controls collection of the PlaceHolder control.
ControlPlaceHolder.Controls.Add(NewTree)
End Sub
Sub Node_Change(ByVal sender As Object, ByVal e As EventArgs)
' Retrieve the TreeView control from the Controls collection of the PlaceHolder control.
Dim LocalTree As TreeView = CType(ControlPlaceHolder.FindControl("BookTreeView"), TreeView)
' Display the selected node.
Message.Text = "You selected: " & LocalTree.SelectedNode.Text
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>TreeView Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeView Constructor Example</h3>
<asp:PlaceHolder id="ControlPlaceHolder" runat="server">
</asp:PlaceHolder>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Book.xml"
runat="server">
</asp:XmlDataSource>
<br /><br />
<asp:Label id="Message" runat="server"/>
</form>
</body>
</html>
O exemplo de código a seguir fornece dados XML de exemplo para o exemplo anterior.
<Book Title="Book Title">
<Chapter Heading="Chapter 1">
<Section Heading="Section 1">
</Section>
<Section Heading="Section 2">
</Section>
</Chapter>
<Chapter Heading="Chapter 2">
<Section Heading="Section 1">
</Section>
</Chapter>
</Book>
Comentários
Use o TreeView construtor para criar e inicializar uma nova instância da TreeView classe. Para adicionar um TreeView controle a uma página dinamicamente, crie um novo TreeView objeto, defina suas propriedades e adicione-o Control.Controls à coleção de um controle de contêiner, como o PlaceHolder controle.