asp中CodePage、Response.CodePage和Session.CodePage区别介绍

关于CodePage、Response.CodePage和Session.CodePage三者的区别，MSDN说明如下：

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影响静态文本，Response.CodePage影响动态文本，Session.CodePage的作用和Response.CodePage相同，只是它的作用范围更大，影响同一会话的所有响应。

1、CodePage和Response.CodePage的测试

<%@ CodePage=65001 %>
<%
    Response.Charset="utf-8"   
   
    Response.CodePage = 936
    Response.Write("这是动态文本。")   
%>
这是静态文本。

<%@ CodePage=65001 %>
<%
    Response.Charset="gb2312"   
   
    Response.CodePage = 936
    Response.Write("这是动态文本。")   
%>

这是静态文本。

<%@ CodePage=936 %>
<%
    Response.Charset="gb2312"   
   
    Response.CodePage = 936
    Response.Write("这是动态文本。")   
%>
这是静态文本。

说明：网页文件编码为UTF-8。

2、Response.CodePage和Session.CodePage的测试

<%
    Response.Charset="gb2312"  
   
    Session.CodePage = 65001
    Response.CodePage = 936
    Response.Write("这是动态文本。")   
%>
这是静态文本。

<%
    Response.Charset="gb2312"  
   
    Response.CodePage = 936
    Session.CodePage = 65001
    Response.Write("这是动态文本。")   
%>
这是静态文本。

3、CodePage、Response.CodePage和Session.CodePage取值顺序

若未设置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.

若未设置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.

若未设置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

还是看MSDN的说明：

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.