using System;

using System.Net;

using System.Web;

using System.Text;

using System.Collections.Specialized;

public class Program

{

    public static void Main()

    {

        //StringBuilder postdata = new StringBuilder();

        //postdata.Append(HttpUtility.UrlEncode(String.Format("param={0}&", "test value 123 *&$# ")));

        NameValueCollection outgoingQueryString = HttpUtility.ParseQueryString(String.Empty);

        outgoingQueryString.Add("field1","value 1 !@#$%^' ");

        outgoingQueryString.Add("field2", "value 2");

        string postdata = outgoingQueryString.ToString();

        Console.WriteLine(postdata);

    }

}