TreeNode.ExpandAll 方法
定义
重要
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展开当前节点及其所有子节点。
public:
void ExpandAll();public void ExpandAll ();member this.ExpandAll : unit -> unitPublic Sub ExpandAll ()示例
下面的代码示例演示如何使用 ExpandAll 该方法以编程方式扩展控件中的 TreeView 节点及其所有子节点。 若要使此示例正常工作，必须将下面的示例 XML 数据复制到名为Book.xml的文件。
<%@ 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 Data_Bound(Object sender, TreeNodeEventArgs e)
{
// Determine the depth of a node as it is bound to data.
// If the depth is 1, expand the node.
if(e.Node.Depth == 1)
{
// Expand the node using the ExpandAll method.
e.Node.ExpandAll();
}
else
{
// Collapse the node using the CollapseAll method.
e.Node.CollapseAll();
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>TreeNode ExpandAll and CollapseAll Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeNode ExpandAll and CollapseAll Example</h3>
<h5>Expand the root node. Notice that the child nodes are already expanded.</h5>
<asp:TreeView id="BookTreeView"
DataSourceID="BookXmlDataSource"
OnTreeNodeDataBound="Data_Bound"
runat="server">
<DataBindings>
<asp:TreeNodeBinding DataMember="Book" TextField="Title"/>
<asp:TreeNodeBinding DataMember="Chapter" TextField="Heading"/>
<asp:TreeNodeBinding DataMember="Section" TextField="Heading"/>
</DataBindings>
</asp:TreeView>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Book.xml"
runat="server">
</asp:XmlDataSource>
</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 Data_Bound(ByVal sender As Object, ByVal e As TreeNodeEventArgs)
' Determine the depth of a node as it is bound to data.
' If the depth is 1, expand the node.
If e.Node.Depth = 1 Then
' Expand the node using the ExpandAll method.
e.Node.ExpandAll()
Else
' Collapse the node using the CollapseAll method.
e.Node.CollapseAll()
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>TreeNode ExpandAll and CollapseAll Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>TreeNode ExpandAll and CollapseAll Example</h3>
<h5>Expand the root node. Notice that the child nodes are already expanded.</h5>
<asp:TreeView id="BookTreeView"
DataSourceID="BookXmlDataSource"
OnTreeNodeDataBound="Data_Bound"
runat="server">
<DataBindings>
<asp:TreeNodeBinding DataMember="Book" TextField="Title"/>
<asp:TreeNodeBinding DataMember="Chapter" TextField="Heading"/>
<asp:TreeNodeBinding DataMember="Section" TextField="Heading"/>
</DataBindings>
</asp:TreeView>
<asp:XmlDataSource id="BookXmlDataSource"
DataFile="Book.xml"
runat="server">
</asp:XmlDataSource>
</form>
</body>
</html>
下面的代码是上一个示例的示例 XML 数据。
<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>
注解
使用此方法 ExpandAll 可方便地扩展当前节点及其所有子节点。
备注
作为替代方法，还可以将当前节点及其每个子节点的属性设置为 Expanded true。
若要仅扩展当前节点，请考虑使用 Expand 该方法。
ExpandAll 将展开整个树中的所有节点。