Get Asp Ajax/JSON in WebRequest example

i like to do my crawling with WebRequest, so i found an ajax i need, and if u never noticed, Asp Ajax Controls use JSON, so.. how u do that? 1st of all take a look at my normal WebRequest method: http://bresleveloper.blogspot.com/2012/04/ease-of-webrequest.html
atcualy there r only 2 things to change, the ContentType and the RequestStream.
ContentType is easy => "application/json; charset=utf-8"

now the stream must be built differently, as a JSON, and dont use the JavaScriptSerializer Serialize mehtod cuz u'll get key-pair and thats not what u want, instead lets change all the part with the

StringBuilder sbData until we get this:

*Note - do remember that the members comes like this:
Dictionary<string, object> and object again becomes this dic until he become an ArrayList of string.

bool first = true;

StringBuilder sbData = new StringBuilder();

foreach (String key in parameters.AllKeys)

{

     if (first)

     {
            first = false;

            sbData.Append("{");

     }
     else

            sbData.Append(",");

     sbData.Append("\"" + key + "\"");

     sbData.Append(":");

     sbData.Append("\"" + parameters[key] + "\"");

}
sbData.Append("}");

if ("POST" == request.Method)

{
       request.ContentType = "application/json; charset=utf-8";

       request.ContentLength = sbData.Length;
}
tada!!!!

p.s. - if u want to send lists in parameters u can change parameters to

Dictionary<string, List<string>>  and do this:
bool first = true;                    
StringBuilder sbData = new StringBuilder();
foreach (KeyValuePair<string, List<string>> entry in parameters)                    
{
      if (first)
      {                            
             first = false;
             sbData.Append("{");                        
      }
      else
             sbData.Append(",");
      sbData.Append("\"" + entry.Key + "\"");
      if (entry.Value.Count > 1)                        
      {
             sbData.Append(":[");
             bool firstValue = true;
             foreach (string val in entry.Value)
            {
                       if (firstValue)                                    
                               firstValue = false;
                       else                                    
                               sbData.Append(",");
                       sbData.Append("\"" + val + "\"");
             }
             sbData.Append("]");
       }
       else                            
             sbData.Append(":\"" + entry.Value[0] + "\"");
}                    
sbData.Append("}");