.net中实现RSS方法

引用
如何在.net动态网站中实现RSS呢？主要思想是编写一个能够自动按照RSS格式生成xml文档的通用类。具体步骤如下：

步骤一：创建RSS通用类
C#代码

using System;  
using System.IO;  
using System.Data;  
using System.Xml;  
using System.Collections.Generic;  
using System.Text;

public class Rss {  
public Stream OutputStream;  
public string RssTitle;  
public string PublisherUrl;  
public string Description;  
public string Copyright;  
public string Generator;  
public DataSet ItemSource;  
public string ItemTitleField;  
public string ItemUrlField;  
public string ItemDescriptionField;  
public string ItemPublicationDateField;  
public string ItemAuthor;

public static void PublishRss(Rss r){  
//创建了 System.Xml.XmlTextWriter类的实例,这个类是撰写XML文档的快速方式  
XmlTextWriter writer = new XmlTextWriter(r.OutputStream,  Encoding.UTF8);
 
//这个方法写入XML 1.0版本的声明,即<?xml
version="1.0" encoding="utf-8"?>  
writer.WriteStartDocument();  
//WriteStartElement这个方法写入指定标签的起始标记。  
writer.WriteStartElement("rss");  
//这个方法为当前打开的标签写入属性。  
writer.WriteAttributeString("version", "2.0");  
writer.WriteStartElement("channel");  
//这个方法写入一个起始标记和一个结束标记  
writer.WriteElementString("title", r.RssTitle);  
writer.WriteElementString("link", r.PublisherUrl);  
writer.WriteElementString("description", r.Description);  
writer.WriteElementString("copyright", r.Copyright);  
writer.WriteElementString("generator", r.Generator);

foreach (DataRow row in r.ItemSource.Tables[0].Rows) {  
writer.WriteStartElement("item");  
writer.WriteElementString("author", row[r.ItemAuthor].ToString());
 
writer.WriteElementString("title", row[r.ItemTitleField].ToString());
 
writer.WriteElementString("link", row[r.ItemUrlField].ToString());
 
writer.WriteElementString("description", row[r.ItemDescriptionField].ToString());
 
writer.WriteElementString("pubDate",
Convert.ToDateTime(row[r.ItemPublicationDateField]).ToString("dd MMM yyyy
hh:mm:00 "));  
writer.WriteEndElement();  
}  
//写入channel标记的结束标记  
writer.WriteEndElement();  
//写入RSS标记的结束标记  
writer.WriteEndElement();  
//将所有缓存的output到目的位置  
writer.Flush();  
}  
}

using System;
using System.IO;
using System.Data;
using System.Xml;
using System.Collections.Generic;
using System.Text;

public class Rss {
public Stream OutputStream;
public string RssTitle;
public string PublisherUrl;
public string Description;
public string Copyright;
public string Generator;
public DataSet ItemSource;
public string ItemTitleField;
public string ItemUrlField;
public string ItemDescriptionField;
public string ItemPublicationDateField;
public string ItemAuthor;

public static void PublishRss(Rss r){
//创建了 System.Xml.XmlTextWriter类的实例,这个类是撰写XML文档的快速方式
XmlTextWriter writer = new XmlTextWriter(r.OutputStream,  Encoding.UTF8);
//这个方法写入XML 1.0版本的声明,即<?xml version="1.0"
encoding="utf-8"?>
writer.WriteStartDocument();
//WriteStartElement这个方法写入指定标签的起始标记。
writer.WriteStartElement("rss");
//这个方法为当前打开的标签写入属性。
writer.WriteAttributeString("version", "2.0");
writer.WriteStartElement("channel");
//这个方法写入一个起始标记和一个结束标记
writer.WriteElementString("title", r.RssTitle);
writer.WriteElementString("link", r.PublisherUrl);
writer.WriteElementString("description", r.Description);
writer.WriteElementString("copyright", r.Copyright);
writer.WriteElementString("generator", r.Generator);

foreach (DataRow row in r.ItemSource.Tables[0].Rows) {
writer.WriteStartElement("item");
writer.WriteElementString("author", row[r.ItemAuthor].ToString());
writer.WriteElementString("title", row[r.ItemTitleField].ToString());
writer.WriteElementString("link", row[r.ItemUrlField].ToString());
writer.WriteElementString("description",
row[r.ItemDescriptionField].ToString());
writer.WriteElementString("pubDate",
Convert.ToDateTime(row[r.ItemPublicationDateField]).ToString("dd MMM yyyy
hh:mm:00 "));
writer.WriteEndElement();
}
//写入channel标记的结束标记
writer.WriteEndElement();
//写入RSS标记的结束标记
writer.WriteEndElement();
//将所有缓存的output到目的位置
writer.Flush();
}
}

Note:这里pubDate的日期格式很重要，当你按上面的代码对pubDate进行格式转换的时候， 假如数据库中是 2007-9-14 9:58，那么在英文操作系统下，会转换成 “14 Sep 2007 9:58”, 这个是没有问题的。但在中文操作系统下，就变成了 “14 九月 2007 9:58”。导致的结果就是在IE7中点开rss源的 时候，发现日期没有显示。如果你不进行数据格式转换，简单的使用一个 ToString()，结果仍是如此。这里写了一个格式转换代码：
C#代码

public static string GetRssDate(Object date) {  
DateTime rssDate = Convert.ToDateTime(date);  
string[] monthName = { "Jan", "Feb", "Mar",
"Apr", "May", "Jun", "Jul",
"Aug", "Sep", "Oct", "Nov",
"Dec" };

StringBuilder sb = new StringBuilder();  
sb.Append(rssDate.Day);  
sb.Append(" ");  
sb.Append(monthName[Convert.ToInt32(rssDate.Month) - 1]);  
sb.Append(" ");  
sb.Append(rssDate.Year);  
sb.Append(" ");  
sb.Append(rssDate.ToLongTimeString());

return sb.ToString();  
}

public static string GetRssDate(Object date) {
DateTime rssDate = Convert.ToDateTime(date);
string[] monthName = { "Jan", "Feb", "Mar",
"Apr", "May", "Jun", "Jul",
"Aug", "Sep", "Oct", "Nov",
"Dec" };

StringBuilder sb = new StringBuilder();
sb.Append(rssDate.Day);
sb.Append(" ");
sb.Append(monthName[Convert.ToInt32(rssDate.Month) - 1]);
sb.Append(" ");
sb.Append(rssDate.Year);
sb.Append(" ");
sb.Append(rssDate.ToLongTimeString());

return sb.ToString();
}

步骤二：创建web窗体（RSS.aspx)
1.在RSS.aspx中删出除第一行外的所有代码
2.在RSS.aspx中实例化RSS类
C#代码

protected void Page_Load(object sender, EventArgs e){  
//GetDataSet从数据库筛选出RSS源所需的相关内容如：aritcle,Url,description,pubDate.  
DataSet ds = GetDataSet();  
Rss rss = new Rss();  
rss.OutputStream = Response.OutputStream;  
rss.RssTitle = "DotNetBips.com Latest Articles";  
rss.PublisherUrl = Request.Url.Host;  
rss.Description = "DotNetBips.com - Applying .NET";  
rss.Copyright = "Copyright (C) DotNetBips.com.";  
rss.Generator = "DotNetBips.com RSS Generator";  
rss.ItemSource = ds;  
rss.ItemTitleField = "Title";  
rss.ItemDescriptionField = "Description";  
rss.ItemPublicationDateField = "Pubdate";  
rss.ItemUrlField = "Url";  
rss.ItemAuthor = "Author";  
Response.ContentEncoding = System.Text.Encoding.UTF8;  
Response.ContentType = "text/xml";  
//调用Rss类中的静态方法  
Rss.PublishRss(rss);  
Response.End();  
}

protected void Page_Load(object sender, EventArgs e){
//GetDataSet从数据库筛选出RSS源所需的相关内容如：aritcle,Url,description,pubDate.
DataSet ds = GetDataSet();
Rss rss = new Rss();
rss.OutputStream = Response.OutputStream;
rss.RssTitle = "DotNetBips.com Latest Articles";
rss.PublisherUrl = Request.Url.Host;
rss.Description = "DotNetBips.com - Applying .NET";
rss.Copyright = "Copyright (C) DotNetBips.com.";
rss.Generator = "DotNetBips.com RSS Generator";
rss.ItemSource = ds;
rss.ItemTitleField = "Title";
rss.ItemDescriptionField = "Description";
rss.ItemPublicationDateField = "Pubdate";
rss.ItemUrlField = "Url";
rss.ItemAuthor = "Author";
Response.ContentEncoding = System.Text.Encoding.UTF8;
Response.ContentType = "text/xml";
//调用Rss类中的静态方法
Rss.PublishRss(rss);
Response.End();
}

步骤三：链接RSS.aspx
在如上两步操作后，RSS的实现已经完成了99%,剩下的就是在需要放置RSS源的页面中（如default.aspx)放置如下代码：
C#代码

1. <link rel="alternate" type="application/rss+xml"
title="Your Web Site’s RSS Feed Title " href="rss.aspx"
/>