public String ExecutePost()
{
Random rd = new Random();
int rd_i = rd.Next();
String nonce = Convert.ToString(rd_i);
String timestamp = Convert.ToString(ConvertDateTimeInt(DateTime.Now));
String signature = GetHash(this.appSecret + nonce + timestamp);
//ServicePointManager.ServerCertificateValidationCallback += ValidateRemoteCertificate;
//ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
WebClient myWebClient = new WebClient();
myWebClient.Headers.Add("App-Key", this.appkey);
myWebClient.Headers.Add("Nonce", nonce);
myWebClient.Headers.Add("Timestamp", timestamp);
myWebClient.Headers.Add("Signature", signature);
myWebClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
byte[] byteArray = Encoding.UTF8.GetBytes(this.postStr);
byte[] responseArray = myWebClient.UploadData(this.methodUrl, "POST", byteArray);
return Encoding.UTF8.GetString(responseArray);
}