title: remove html node from htmldocument :HTMLAgilityPack
body: <p>In my code, I want to remove the img tag which doesn't have src value.
      I am using <strong>HTMLAgilitypack's HtmlDocument</strong> object.
      I am finding the img which doesn't have src value and trying to remove it.. but it     gives me error Collection was modified; enumeration operation may not execute.
      Can anyone help me for this?
      The code which I have used is:</p>
  
  <pre><code>foreach (HtmlNode node in doc.DocumentNode.DescendantNodes())
  {
      if (node.Name.ToLower() == "img")
      {                            
             string src = node.Attributes["src"].Value;
             if (string.IsNullOrEmpty(src))
             {
                 node.ParentNode.RemoveChild(node, false);    
             }
     }
     else
     {
               ..........// i am performing other operations on document
     }
  }
  </code></pre>