you can send huge data also with this trick..
Response.Clear();
StringBuilder sb = new StringBuilder();
sb.Append("<html>");
sb.AppendFormat(@"<body onload='document.forms[""form""].submit()'>");
sb.AppendFormat("<form name="form" action='{0}' method='post'>",postbackUrl);
sb.AppendFormat("<input type="hidden" name="id" value="{0}">", id);
// Other params go here
sb.Append("</form>");
sb.Append("</body>");
sb.Append("</html>");
Response.Write(sb.ToString());
Response.End();