TreeView.TreeNodeExpanded 事件
定义
重要
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在 TreeView 控件中展开某个节点时发生。
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 事件类型
示例
下面的代码示例演示如何在用户展开 控件中的节点时使用 TreeNodeExpanded 事件更新 控件的内容Label。TreeView
<%@ 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>
注解
在 TreeNodeExpanded 控件中 TreeView 展开节点时，将引发 事件。 这允许你提供一个事件处理方法，该方法在发生此事件时执行自定义例程。
注意
SelectAction如果节点的 属性设置为 TreeNodeSelectAction.Expand 或 TreeNodeSelectAction.SelectExpand，则TreeNodeExpanded当在 控件中TreeView单击该节点时，也会引发 该事件。
有关如何处理事件的详细信息，请参阅 处理和引发事件。
