使用 XmlDataSource 控件筛选数据
更新：2007 年 11 月
可通过将 XmlDataSource 控件的 XPath 属性设置为 XPath 筛选表达式，来筛选该控件公开的 XML 数据。如果已指定可扩展样式表语言 (XSL) 样式表来转换 XmlDataSource 控件公开的数据，则在转换后会应用 XPath 筛选表达式。
下面的代码示例演示绑定到 TreeView 控件的 XmlDataSource 控件。XML 数据是使用 XPath 查询筛选的。
<%@ 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 SelectRegion(sender As Object, e As EventArgs)
If RegionDropDownList.SelectedValue = "(Show All)" Then
PeopleDataSource.XPath = "/People/Person"
Else
Dim selectedValue As String = ""
Select Case RegionDropDownList.SelectedValue
Case "CA"
selectedValue = "CA"
Case "HI"
selectedValue = "HI"
Case "WA"
selectedValue = "WA"
Case Else
' Invalid value.
End Select
PeopleDataSource.XPath = "/People/Person[Address/Region='" & selectedValue & "']"
End If
PeopleTreeView.DataBind()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<table border="0" cellpadding="3">
<tr>
<td valign="top">
<b>Select Region:</b>
<asp:DropDownList runat="server" id="RegionDropDownList" AutoPostBack="True"
OnSelectedIndexChanged="SelectRegion">
<asp:ListItem Selected="True">(Show All)</asp:ListItem>
<asp:ListItem>CA</asp:ListItem>
<asp:ListItem>HI</asp:ListItem>
<asp:ListItem>WA</asp:ListItem>
</asp:DropDownList>
</td>
<td valign="top">
<asp:XmlDataSource
id="PeopleDataSource"
runat="server"
XPath="/People/Person"
DataFile="~/App_Data/people.xml" />
<asp:TreeView
id="PeopleTreeView"
runat="server"
DataSourceID="PeopleDataSource">
<DataBindings>
<asp:TreeNodeBinding DataMember="LastName" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="FirstName" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Street" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="City" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Region" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="ZipCode" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Title" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Description" TextField="#InnerText" />
</DataBindings>
</asp:TreeView>
</td>
</tr>
</table>
</form>
</body>
</html>
<%@ 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 SelectRegion(object sender, EventArgs e)
{
if (RegionDropDownList.SelectedValue == "(Show All)")
PeopleDataSource.XPath = "/People/Person";
else
{
string selectedValue = "";
switch (RegionDropDownList.SelectedValue)
{
case "CA":
selectedValue = "CA";
break;
case "HI":
selectedValue = "HI";
break;
case "WA":
selectedValue = "WA";
break;
default:
// Invalid value.
break;
}
PeopleDataSource.XPath = "/People/Person[Address/Region='" + selectedValue + "']";
}
PeopleTreeView.DataBind();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<table border="0" cellpadding="3">
<tr>
<td valign="top">
<b>Select Region:</b>
<asp:DropDownList runat="server" id="RegionDropDownList" AutoPostBack="True"
OnSelectedIndexChanged="SelectRegion">
<asp:ListItem Selected="True">(Show All)</asp:ListItem>
<asp:ListItem>CA</asp:ListItem>
<asp:ListItem>HI</asp:ListItem>
<asp:ListItem>WA</asp:ListItem>
</asp:DropDownList>
</td>
<td valign="top">
<asp:XmlDataSource
id="PeopleDataSource"
runat="server"
XPath="/People/Person"
DataFile="~/App_Data/people.xml" />
<asp:TreeView
id="PeopleTreeView"
runat="server"
DataSourceID="PeopleDataSource">
<DataBindings>
<asp:TreeNodeBinding DataMember="LastName" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="FirstName" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Street" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="City" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Region" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="ZipCode" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Title" TextField="#InnerText" />
<asp:TreeNodeBinding DataMember="Description" TextField="#InnerText" />
</DataBindings>
</asp:TreeView>
</td>
</tr>
</table>
</form>
</body>
</html>