asp中CodePage、Response.CodePage和Session.CodePage區別介紹

關於CodePage、Response.CodePage和Session.CodePage三者的區別，MSDN說明如下：

Setting @CODEPAGE explicitly affects literal strings in a single response. Response.CodePage affects dynamic strings in a single response, and Session.CodePage affects dynamic strings in all responses in a session.

大意是CodePage影響靜態文本，Response.CodePage影響動態文本，Session.CodePage的作用和Response.CodePage相同，只是它的作用範圍更大，影響同一會話的所有響應。

1、CodePage和Response.CodePage的測試

<%@ CodePage=65001 %>
<%
    Response.Charset="utf-8"   
   
    Response.CodePage = 936
    Response.Write("這是動態文本。")   
%>
這是靜態文本。

<%@ CodePage=65001 %>
<%
    Response.Charset="gb2312"   
   
    Response.CodePage = 936
    Response.Write("這是動態文本。")   
%>

這是靜態文本。

<%@ CodePage=936 %>
<%
    Response.Charset="gb2312"   
   
    Response.CodePage = 936
    Response.Write("這是動態文本。")   
%>
這是靜態文本。

說明：網頁檔案編碼為UTF-8。

2、Response.CodePage和Session.CodePage的測試

<%
    Response.Charset="gb2312"  
   
    Session.CodePage = 65001
    Response.CodePage = 936
    Response.Write("這是動態文本。")   
%>
這是靜態文本。

<%
    Response.Charset="gb2312"  
   
    Response.CodePage = 936
    Session.CodePage = 65001
    Response.Write("這是動態文本。")   
%>
這是靜態文本。

3、CodePage、Response.CodePage和Session.CodePage取值順序

若未設定CodePage：

If @CODEPAGE is not explicitly set in a page, it is implicitly set by the AspCodePage metabase property or by the system ANSI code page.

若未設定Response.CodePage：

If Response.CodePage is not explicitly set in a page, it is implicitly set by Session.CodePage, if sessions are enabled. If sessions are not enabled, Response.CodePage is set by @CodePage, if @CodePage is present in the page. If there is no @CodePage in the page, Response.CodePage is set by the AspCodePage metabase property. If the AspCodePage metabase property is not set, or set to 0, Response.CodePage is set by the system ANSI codepage.

若未設定Session.CodePage：

If Session.CodePage is not explicitly set on a page, it is implicitly set by the AspCodePage metabase property. If the AspCodePage property is not set, or set to 0, Session.CodePage is set by the system ANSI code page. Session.CodePage is no longer implicitly set by @CodePage, as it was for IIS 5.0 and earlier versions. This change was made because one @CodePage could change the code page for an entire session. Now, @CodePage and Response.CodePage affect only single responses, while Session.CodePage affects all responses in a session.

4、Response.Charset的作用

還是看MSDN的說明：

If the code page is set in a page, then Response.Charset should also be set. The code page value specifies to IIS how to encode the data when building the response, and the charset value tells the browser how to decode the data when displaying the response. The CharsetName of Response.Charset must match the code page value, or mixed characters are displayed in the browser.