利用Ajax无刷新更新rss阅读

上次总结过rss的读取，现在总结ajax无刷新更新rss阅读

代码如下：

ashx代码：

public class GetRss : IHttpHandler
{

    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "text/plain";
        string url = "http://rss.sina.com.cn/news/china/focus15.xml";
        XmlDocument document = new XmlDocument();
        document.Load(url);
        XmlNodeList list = document.GetElementsByTagName("item");
        if (document.HasChildNodes)
        {
            DataTable dt = CreateXmlTable();
            foreach (XmlNode var in list)
            {
                if (var.HasChildNodes)
                {
                    DataRow dr = dt.NewRow();
                    XmlNodeList chidList = var.ChildNodes;
                    foreach (XmlNode v1 in chidList)
                    {
                        switch (v1.Name)
                        {
                            case "title":
                                dr["title"] = v1.InnerText;
                                break;
                            case "link":
                                dr["Link"] = v1.InnerText;
                                break;
                            case "author":
                                dr["author"] = v1.InnerText;
                                break;
                            case "category":
                                dr["summary"] = v1.InnerText;
                                break;
                            case "description":
                                dr["content"] = v1.InnerText;
                                break;
                            case "pubDate":
                                dr["published"] = v1.InnerText;
                                break;
                            default:
                                break;
                        }
                    }
                    dt.Rows.Add(dr);
                }
            }
            WriteToSQL(dt);
        }
        string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["Conn"].ConnectionString;
        DataSet ds = new DataSet();
        using (SqlConnection con = new SqlConnection(connectionString))
        {
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "SELECT top 10 * FROM RSS WHERE summary='国内要闻' order by [published] desc";
            SqlDataAdapter da = new SqlDataAdapter(cmd);

            da.Fill(ds);
        }
        string html = "";
        if (ds == null || ds.Tables.Count <= 0 || ds.Tables[0].Rows.Count <= 0)
        {
            html = "";
        }
        for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
        {
            html = html + "<div><div>";
            html = html + "<a  href='" + ds.Tables[0].Rows[i]["link"].ToString() + "' target='_blank'>" + ds.Tables[0].Rows[i]["title"].ToString() + "</a><br/><br/></div><div>" + ds.Tables[0].Rows[i]["content"].ToString() + "</div></div><hr>";
        }
        context.Response.Write(html);
    }
    public void WriteToSQL(DataTable dt)
    {

        if (dt == null || dt.Rows.Count <= 0)
        {
            return;
        }
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            RssMod model = new RssMod();
            model.Link = dt.Rows[i]["link"].ToString();
            model.Author = dt.Rows[i]["author"].ToString();
            model.Content = dt.Rows[i]["content"].ToString();
            model.Published = Convert.ToDateTime(dt.Rows[i]["published"].ToString());
            model.Summary = dt.Rows[i]["summary"].ToString();
            model.Title = dt.Rows[i]["title"].ToString();
            if (!IsExistsByLink(model.Link))
            {
                ExcuteNonQuery(model);
            }
        }
    }
    public void ExcuteNonQuery(RssMod model)
    {
        string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["Conn"].ConnectionString;
        using (System.Data.SqlClient.SqlConnection con = new SqlConnection(connectionString))
        {
            con.Open();
            System.Data.SqlClient.SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "INSERT INTO Rss([link],[title],[summary],[author],[content],[published]) VALUES(@link,@title,@summary,@author,@content,@published)";
            SqlParameter[] sp ={ 
            new SqlParameter("@link",SqlDbType.NVarChar,300),
                    new SqlParameter("@title",SqlDbType.NVarChar,200),
                new System.Data.SqlClient.SqlParameter("@summary",SqlDbType.NVarChar,4000),
                new SqlParameter("@author",SqlDbType.NVarChar,50),
                new SqlParameter("@content",SqlDbType.NVarChar,4000),
                new SqlParameter("@published",SqlDbType.DateTime)
            };
            sp[0].Value = model.Link;
            sp[1].Value = model.Title;
            sp[2].Value = model.Summary;
            sp[3].Value = model.Author;
            sp[4].Value = model.Content;
            sp[5].Value = Convert.ToDateTime(model.Published);
            cmd.Parameters.AddRange(sp);
            cmd.ExecuteNonQuery();
        }
    }
    public bool IsExistsByLink(string link)
    {
        string ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["Conn"].ConnectionString.ToString();
        using (SqlConnection con = new SqlConnection(ConnectionString))
        {
            con.Open();
            string strSql = String.Format("SELECT COUNT(0) FROM RSS WHERE LINK='{0}'", link);
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = strSql;
            object ob = cmd.ExecuteScalar();
            return Convert.ToInt32(ob) > 0;
        }
    }
    public DataTable CreateXmlTable()
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Link", typeof(string));
        dt.Columns.Add("title", typeof(string));
        dt.Columns.Add("summary", typeof(string));
        dt.Columns.Add("author", typeof(string));
        dt.Columns.Add("content", typeof(string));
        dt.Columns.Add("published", typeof(string));
        return dt;
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}
public class RssMod
{
    public RssMod()
    {
    }
    private string link;
    public string Link
    {
        get { return link; }
        set { link = value; }
    }

    private string title;
    public string Title
    {
        get { return title; }
        set { title = value; }
    }

    private string summary;
    public string Summary
    {
        get { return summary; }
        set { summary = value; }
    }

    private string author;
    public string Author
    {
        get { return author; }
        set { author = value; }
    }

    private string content;
    public string Content
    {
        get { return content; }
        set { content = value; }
    }

    private DateTime published;
    public DateTime Published
    {
        get { return published; }
        set { published = value; }
    }
}

页面代码：

<head runat="server">
    <title>无标题页</title>

    <script src="js/jquery-1.4.2.min.js" type="text/javascript"></script>

    <script language="javascript" type="text/javascript">
    window.setInterval('GetXml()',5000);
   function GetXml(){
   $.get("GetRss.ashx",function(data){
  $("#rssItem").html(data);
   });
   }
    </script>

</head>
<body >
    <form id="form1" runat="server" method="post">
        <div align="center">
            <table cellpadding="0" cellspacing="0" border="0" width="80%">
                <tr>
                    <td>
                        <div id="rssItem" style="width: 80%;">
                        </div>
                    </td>
                </tr>
            </table>
        </div>
    </form>
</body>
</html>