下面的代码示例演示如何使用 PartialCachingAttribute。此示例包括三个部分：
示例的第一部分演示一个分部类，该分部类继承自 UserControl 基类，并且应用了 PartialCachingAttribute 属性。在此示例中，该属性指定用户控件将缓存 20 秒。
' Filename is partialcache.vb
' Create a code-behind user control that is cached
' for 20 seconds using the PartialCachingAttribute class.
' This control uses a DataGrid server control to display
' XML data.
Imports System
Imports System.IO
Imports System.Data
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace Samples.AspNet.VB.Controls
' Set the PartialCachingAttribute.Duration property to 20 seconds.
<PartialCaching(20)> _
Partial Class ctlMine
Inherits UserControl
Protected Sub Page_Load(ByVal Src As [Object], ByVal E As EventArgs)
Dim ds As New DataSet()
Dim fs As New FileStream(Server.MapPath("schemadata.xml"), FileMode.Open, FileAccess.Read)
Dim reader As New StreamReader(fs)
ds.ReadXml(reader)
fs.Close()
Dim [Source] As New DataView(ds.Tables(0))
' Use the LiteralControl constructor to create a new
' instance of the class.
Dim myLiteral As New LiteralControl()
' Set the LiteralControl.Text property to an HTML
' string and the TableName value of a data source.
myLiteral.Text = "<h6><font face=verdana>Caching an XML Table: " & [Source].Table.TableName & " </font></h6>"
MyDataGrid.DataSource = [Source]
MyDataGrid.DataBind()
TimeMsg.Text = DateTime.Now.ToString("G")
End Sub 'Page_Load
End Class 'ctlMine
End Namespace
// [filename partialcache.cs]
// Create a code-behind user control that is cached
// for 20 seconds using the PartialCachingAttribute class.
// This control uses a DataGrid server control to display
// XML data.
using System;
using System.IO;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Samples.AspNet.CS.Controls
{
// Set the PartialCachingAttribute.Duration property to 20 seconds.
[PartialCaching(20)]
public partial class ctlMine : UserControl
{
protected void Page_Load(Object Src, EventArgs E)
{
DataSet ds = new DataSet();
FileStream fs = new FileStream(Server.MapPath("schemadata.xml"), FileMode.Open, FileAccess.Read);
StreamReader reader = new StreamReader(fs);
ds.ReadXml(reader);
fs.Close();
DataView Source = new DataView(ds.Tables[0]);
// Use the LiteralControl constructor to create a new
// instance of the class.
LiteralControl myLiteral = new LiteralControl();
// Set the LiteralControl.Text property to an HTML
// string and the TableName value of a data source.
myLiteral.Text = "<h6><font face=verdana>Caching an XML Table: " + Source.Table.TableName + " </font></h6>";
MyDataGrid.DataSource = Source;
MyDataGrid.DataBind();
TimeMsg.Text = DateTime.Now.ToString("G");
}
}
}
// [filename partialcache.jsl]
// Create a code-behind user control that is cached
// for 20 seconds using the PartialCachingAttribute class.
// This control uses a DataGrid server control to display
// XML data.
import System.*;
import System.IO.*;
import System.Data.*;
import System.Web.*;
import System.Web.UI.*;
import System.Web.UI.WebControls.*;
// Set the PartialCachingAttribute.Duration property to 20 seconds.
/** @attribute PartialCaching(20)
*/
public class ctlMine extends UserControl
{
public DataGrid myDataGrid;
public Label timeMsg;
protected void Page_Load(Object src, EventArgs e)
{
DataSet ds = new DataSet();
FileStream fs = new FileStream(get_Server().MapPath("schemadata.xml"),
FileMode.Open, FileAccess.Read);
StreamReader reader = new StreamReader(fs);
ds.ReadXml(reader);
fs.Close();
DataView source = new DataView(ds.get_Tables().get_Item(0));
// Use the LiteralControl constructor to create a new
// instance of the class.
LiteralControl myLiteral = new LiteralControl();
// Set the LiteralControl.Text property to an HTML
// string and the TableName value of a data source.
myLiteral.set_Text("<h6><font face=verdana>Caching an XML Table: "
+ source.get_Table().get_TableName() + " </font></h6>");
myDataGrid.set_DataSource(source);
myDataGrid.DataBind();
timeMsg.set_Text(DateTime.get_Now().ToString("G"));
} //Page_Load
} //ctlMine
示例的第二部分显示一个用户控件，该控件在前面的示例中用来演示用户控件缓存。
<!-- The mark-up .ascx file that displays the output of
the partialcache.vb user control code-behind file. -->
<%@ Control language="vb" inherits="Samples.AspNet.VB.Controls.ctlMine" CodeFile="partialcache.vb.ascx.vb" %>
<ASP:DataGrid id="MyDataGrid" runat="server"
Width="900"
BackColor="#ccccff"
BorderColor="black"
ShowFooter="false"
CellPadding="3"
CellSpacing="0"
Font-Names="Verdana"
Font-Size="8pt"
HeaderStyle-BackColor="#aaaadd"
EnableViewState="false"
/>
<br />
<i>Control last generated on:</i> <asp:label id="TimeMsg" runat="server" />
<!-- The mark-up .ascx file that displays the output of
the partialcache.cs user control code-behind file. -->
<%@ Control language="C#" inherits="Samples.AspNet.CS.Controls.ctlMine" CodeFile="partialcache.cs.ascx.cs" %>
<ASP:DataGrid id="MyDataGrid" runat="server"
Width="900"
BackColor="#ccccff"
BorderColor="black"
ShowFooter="false"
CellPadding="3"
CellSpacing="0"
Font-Names="Verdana"
Font-Size="8pt"
HeaderStyle-BackColor="#aaaadd"
EnableViewState="false"
/>
<br />
<i>Control last generated on:</i> <asp:label id="TimeMsg" runat="server" />
// The mark-up .ascx file that displays the output of
// the partialcache.jsl user control code-behind file.
<%@ Control language="VJ#" inherits="ctlMine" src="partialcache.jsl" %>
<ASP:DataGrid id="myDataGrid" runat="server"
Width="900"
BackColor="#ccccff"
BorderColor="black"
ShowFooter="false"
CellPadding="3"
CellSpacing="0"
Font-Names="Verdana"
Font-Size="8pt"
HeaderStyle-BackColor="#aaaadd"
EnableViewState="false"
/>
<br />
<i>Control last generated on:</i> <asp:label id="timeMsg" runat="server" />
示例的第三部分演示一个承载用户控件的 Web 窗体页。
<!-- The WebForms page that contains the user control generated
by partialcache.vb. -->
<%@ Register TagPrefix="Acme" TagName="Cache" Src="partialcache.vb.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<script language="vb" runat="server">
Sub Page_Load(Src As [Object], E As EventArgs)
TimeMsg.Text = DateTime.Now.ToString("G")
End Sub 'Page_Load
</script>
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<Acme:Cache runat="server"/>
<br />
<i>Page last generated on:</i> <asp:label id="TimeMsg" runat="server" />
</form>
</body>
</html>
<!-- The WebForms page that contains the user control generated
by partialcache.cs. -->
<%@ Register TagPrefix="Acme" TagName="Cache" Src="partialcache.cs.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<script language="C#" runat="server">
void Page_Load(Object Src, EventArgs E ) {
TimeMsg.Text = DateTime.Now.ToString("G");
}
</script>
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<Acme:Cache runat="server"/>
<br />
<i>Page last generated on:</i> <asp:label id="TimeMsg" runat="server" />
</form>
</body>
</html>
// The WebForms page that contains the user control generated
// by partialcache.jsl.
<%@ Register TagPrefix="Acme" TagName="Cache" Src="partialcache.jsl.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<script language="VJ#" runat="server">
void Page_Load(Object src, EventArgs e )
{
TimeMsg.set_Text(DateTime.get_Now().ToString("G"));
} //Page_Load
</script>
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<Acme:Cache runat="server"/>
<br />
<i>Page last generated on:</i> <asp:label id="TimeMsg" runat="server" />
</form>
</body>
</html>