The Code return error A column named 'link' already belongs

Question

 public partial class Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

        try
        {
            DataSet ds = new DataSet();
            ds.ReadXml(@"http://tecnologia.ig.com.br/rss.xml");

            XmlDocument doc = new XmlDocument();
            XmlUrlResolver resolver = new XmlUrlResolver();
            resolver.Credentials = new System.Net.NetworkCredential("bruno", "*****");//intentionally hiding real password from stackoverflow
            doc.XmlResolver = resolver;

            foreach (DataRow dr in ds.Tables["item"].Rows)
            {
                Response.Write("Item TITLE: " + dr["title"].ToString() + "<br />");
                Response.Write("Descrição : " + dr["description"].ToString() + "<br />");
                Response.Write("Data de Publicação: " + dr["pubDate"].ToString() + "<br />");
            }
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }
}

I execute the Code, and the system return two error's
1 - A column named 'link' already belongs to this DataTable: cannot set a nested table name to the same name. 2 - The remote server returned an error: (407) Proxy Authentication Required.

Thanks!

Likely the first error relates to the second. Take a look here for some info about your settings which may remove the second error, and hopefully the first: http://stackoverflow.com/questions/1524566/407-proxy-authentication-required — stevepkr84, Aug 13 '13 at 12:59

score 1 · Accepted Answer · edited Mar 18 '15 at 17:46

1

Just provide an idea for reading RSS Feed:

Create a WebRequest and WebReponse object:

WebRequest request=WebRequest.Create("your url");
WebReponse response=request.GetRespose();

Create a XML document and load the XML document with stream from response object:

Stream rssStream=response.GetResponseStream();
XMLDocument xmlDoc=new XMLDocument();
xmlDoc.Load(rssStream);

Retrieve matching XML nodes from XMLDocument with XMLNodeList:

XmlNodeList xmlNodeList = xmlDoc.SelectNodes("your XPath expression");

Now you can loop the RSS feed items to get what you want:

 for (int i = 0; i < xmlNodeList.Count; i++)
    {
        XmlNode xmlNode;

        xmlNode = xmlNodeList.Item(i).SelectSingleNode("ProductName");
        //xmlNode.InnerText;
    }

edited Mar 18 '15 at 17:46

Sean Kendle

3,538
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answered Aug 13 '13 at 13:02

Sain Pradeep

3,119
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This is the kind of suggestion I'd go with, rather than parsing it into a dataset – Daniel Dawes Aug 13 '13 at 13:03
System.Net.WebProxy proxy = new System.Net.WebProxy(@"ip:door"); proxy.Credentials = new System.Net.NetworkCredential("User", "Pass"); System.Net.WebRequest.DefaultWebProxy = proxy; I solved the problem 1... and the problem number two it is related to the rss web site (rss/XML corrupted) I just changed the link and it worked, thanks anyway – Bruno Casali Aug 13 '13 at 13:49

score 0 · Answer 2 · answered Aug 13 '13 at 12:58

The 2nd problem:

You probably have a corporate proxy, try using this in the web.config:

<system.net>
  <defaultProxy useDefaultCredentials="true" />
</system.net>

As for the 1st problem:

http://forums.asp.net/t/1220157.aspx/1

The issue is likely because XML will allow duplicate nodes and a data table will not allow duplicate columns, so you cannot parse directly to a data table.

I would suggest doing some research into parsing and using XML data before going to far down the data table route

The Code return error A column named 'link' already belongs

2 Answers2

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