Ich versuche a zu extrahierenlink mitxpath aus der unten genannten url

<code>string url = "http://www.album-cover-art.org/search.php?q=Ruin+-+Live+Album+Version+Lamb+of+God"
</code>

Mein Code:

<code>HtmlAgilityPack.HtmlWeb web = new HtmlAgilityPack.HtmlWeb();
HtmlAgilityPack.HtmlDocument htmlDoc = new HtmlAgilityPack.HtmlDocument();
htmlDoc = web.Load(url); //Exception generated here Line 23

if (htmlDoc.DocumentNode != null)
{
  HtmlNode linkNode = htmlDoc.DocumentNode.SelectSingleNode(".//*[@id='related_search_row']/img/@src");
  if (linkNode != null)
        Console.WriteLine(linkNode.InnerText);
}
</code>

Der obige Code wird problemlos kompiliert, aber wenn ich versuche, ihn auszuführen, wird eine Ausnahme generiert

<code>Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object.
</code>

Komplette Stapelverfolgung

<code>System.NullReferenceException: Object reference not set to an instance of an object.
   at HtmlAgilityPack.HtmlDocument.ReadDocumentEncoding(HtmlNode node) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlDocument.cs:line 1916
   at HtmlAgilityPack.HtmlDocument.PushNodeEnd(Int32 index, Boolean close) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlDocument.cs:line 1805
   at HtmlAgilityPack.HtmlDocument.Parse() in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlDocument.cs:line 1468
   at HtmlAgilityPack.HtmlDocument.Load(TextReader reader) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlDocument.cs:line 769
   at HtmlAgilityPack.HtmlWeb.Get(Uri uri, String method, String path, HtmlDocument doc, IWebProxy proxy, ICredentials creds) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1515
   at HtmlAgilityPack.HtmlWeb.LoadUrl(Uri uri, String method, WebProxy proxy, NetworkCredential creds) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1563
   at HtmlAgilityPack.HtmlWeb.Load(String url, String method) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1149
   at HtmlAgilityPack.HtmlWeb.Load(String url) in C:\Source\htmlagilitypack\Trunk\HtmlAgilityPack\HtmlWeb.cs:line 1107
   at ScreenScrapping.Program.Main(String[] args) in c:\Users\ranveer\csharp\ScreenScrapping\ScreenScrapping\Program.cs:line 23
</code>

Meine Frage ist also, warum ich diese Ausnahme erhalte.