System.ArgumentNullException: Value cannot be null.
Parameter name: String
   at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
   at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
   at Tank.Request.ChargeTest.ProcessRequest(HttpContext context) in C:\GG\Code\gg-game-server\Tank.Request\ChargeTest.ashx.cs:line 30