function T_SunnySky_SDK.JoinItems(AParamDic: TDictionary<string, string>): string;

var

  sb : TStringBuilder;

  key :  TPair<string,string>;

begin

   if not Assigned(AParamDic)  then

      Result := ''

   else if AParamDic.Count = 0  then

      Result := ''

   else begin

         sb := TStringBuilder.Create;

         try

             for key in AParamDic do

             begin

                 if sb.Length > 0  then

                   sb.Append('&');

                 sb.Append(key.Key);

                 sb.Append('=');

                 sb.Append(HTTPEncode(key.Value));

             end;

             Result := sb.ToString;

         finally

            sb.Free;

         end;

   end;

end;