Substitution 建構函式
定義
重要
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初始化 Substitution 類別的新執行個體。
public:
Substitution();public Substitution ();Public Sub New ()範例
下列程式代碼範例示範如何以程序設計方式將控件新增 Substitution 至輸出快取的網頁。 當頁面載入時，目前的日期和時間會顯示給標籤中的使用者。 頁面的這個區段只會快取並每 60 秒更新一次。 當 Substitution 控件執行時，它會呼叫 GetCurrentDateTime 方法。 所 GetCurrentDateTime 傳回的字串會顯示給使用者。 頁面的這個區段不會快取，而且會在每次重新整理頁面時更新。
<%@ outputcache duration="60" varybyparam="none" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server" language="C#">
void Page_Load(object sender, System.EventArgs e)
{
// Programmatically create a Substitution control.
Substitution Substitution1 = new Substitution();
// Specify the callback method.
Substitution1.MethodName = "GetCurrentDateTime";
// Add the Substitution control to the controls
// collection of PlaceHolder1.
PlaceHolder1.Controls.Add (Substitution1);
// Display the current date and time in the label.
// Output caching applies to this section of the page.
CachedDateLabel.Text = DateTime.Now.ToString();
}
// The Substitution control calls this method to retrieve
// the current date and time. This section of the page
// is exempt from output caching.
public static string GetCurrentDateTime (HttpContext context)
{
return DateTime.Now.ToString ();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Substitution Class Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>Substitution Constructor Example</h3>
<p>This section of the page is not cached:</p>
<asp:placeholder id="PlaceHolder1"
runat="Server">
</asp:placeholder>
<br />
<p>This section of the page is cached:</p>
<asp:label id="CachedDateLabel"
runat="Server">
</asp:label>
<br /><br />
<asp:button id="RefreshButton"
text="Refresh Page"
runat="Server">
</asp:button>
</form>
</body>
</html>
<%@ outputcache duration="60" varybyparam="none" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server" language="VB">
Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
' Programmatically create a Substitution control.
Dim Substitution1 As New Substitution
' Specify the callback method.
Substitution1.MethodName = "GetCurrentDateTime"
' Add the Substitution control to the controls
' collection of PlaceHolder1.
PlaceHolder1.Controls.Add(Substitution1)
' Display the current date and time in the label.
' Output caching applies to this section of the page.
CachedDateLabel.Text = DateTime.Now.ToString()
End Sub
' The Substitution control calls this method to retrieve
' the current date and time. This section of the page
' is exempt from output caching.
Shared Function GetCurrentDateTime(ByVal context As HttpContext) As String
Return DateTime.Now.ToString()
End Function
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Substitution Constructor Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>Substitution Constructor Example</h3>
<p>This section of the page is not cached:</p>
<asp:placeholder id="PlaceHolder1"
runat="Server">
</asp:placeholder>
<br />
<p>This section of the page is cached:</p>
<asp:label id="CachedDateLabel"
runat="Server">
</asp:label>
<br /><br />
<asp:button id="RefreshButton"
text="Refresh Page"
runat="Server">
</asp:button>
</form>
</body>
</html>
備註
使用建 Substitution 構函式來建立和初始化 類別的新實例 Substitution 。
