CaseStudy(showcase)数据篇-从XML中获取数据

做silvelight也有一段时间了，相册、游戏，刚刚完成的showcase这个小程序算是一个阶段了。这里就以showcase这个项目来做一下CaseStudy。

数据篇-从XML中获取数据

这个项目我的后台用的是asp.net开发。由于规模比较小我的数据层用的是subsonic。用它来做开发会比较敏捷。

这一回我选择的数据方式是asp.net生成xml，用silverlight中的Linq来实例化成具体的类。

这里我以读取类别信息为例子，分为3步：

1. 定义xml

<? xml version="1.0" encoding="utf-8"  ?>
< categories >
< category >< cid > 2 </ cid >< title > Dumex </ title ></ category >
< category >< cid > 1 </ cid >< title > MySVW </ title ></ category >
< category >< cid > 3 </ cid >< title > Microsoft </ title ></ category >
</ categories >


2. 定义实体类

      public   class  Category
    {
         public   int  cid {  get ;  set ; }
         public   string  title {  get ;  set ; }
    }
   


3. 用linq读取

               WebClient client  =   new  WebClient();
               client.DownloadStringAsync( new  Uri(HtmlPage.Document.DocumentUri,  " category.ashx " ));
               client.DownloadStringCompleted  +=   new  DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
               
            void  client_DownloadStringCompleted( object  sender, DownloadStringCompletedEventArgs e)
           {
               XmlReader reader  =  XmlReader.Create( new  StringReader(e.Result));
               XDocument document  =  XDocument.Load(reader);
               var categories  =  from c  in  document.Descendants( " category " )
                                select  new  Category
                                {
                                    cid  =   int .Parse(c.Element( " cid " ).Value),
                                    title  =  c.Element( " title " ).Value
                                };
   
                // todo 
           }    
         
        
   

在这里我选用了ashx来配合subsonic生成xml文件

<% @ WebHandler Language = " C# "  Class = " category "   %>

using  System;
using  System.Web;
using  System.Text;


public   class  category : IHttpHandler {
    StringBuilder sb  =   new  StringBuilder();
     string  templateStr  =   " <category> "   +
                             " <cid>{0}</cid> "   +
                             " <title>{1}</title> "   +
                             " </category> " ;
     public   void  ProcessRequest (HttpContext context) {
        context.Response.ContentType  =   " text/xml " ;
        SC.CategoryCollection cc  =   new  SC.CategoryCollection();
        SubSonic.Query query  =  SC.Category.Query().ORDER_BY( " sortid " ,  " desc " );
        cc.LoadAndCloseReader(query.ExecuteReader());
        sb.AppendLine( " <?xml version=\ " 1.0 \ "  encoding=\ " utf - 8 \ "  ?> " );
        sb.AppendLine( " <categories> " );
         for  ( int  i  =   0 ; i  <  cc.Count; i ++ ) {
            sb.AppendLine( string .Format(templateStr, cc[i].Id, cc[i].Title));
        }
        sb.AppendLine( " </categories> " );
        context.Response.Write(sb.ToString());
    }
 
     public   bool  IsReusable {
         get  {
             return   false ;
        }
    }

}

 

作者：nasa
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