public string CurrrencyConvert(string fromCur, string toCur, double amount, string apikey)
        {
            string resultJson = "";
            Common comm       = new Common();

            using (var conversion = new CConversion())
            {
                if (conversion.ValidateValues(fromCur, toCur, amount, apikey))
                {
                    double rate = 0.0;
                    using (var db = new Cconvert.Model.cconverterEntities())
                    {
                        var crates = db.CurRates.FirstOrDefault(u => u.fromC == fromCur && u.toC == toCur);
                        if (crates != null)
                        {
                            long source  = 0;
                            var  sources = db.sourcemasters.FirstOrDefault(u => u.accesskey == apikey && u.active == true);
                            if (sources != null)
                            {
                                source = sources.id;
                            }
                            else
                            {
                                var logins = db.logindetails.FirstOrDefault(u => u.token == apikey && u.isactive == true);
                                if (logins != null)
                                {
                                    source = logins.sourceid;
                                }
                            }
                            if (source > 0)
                            {
                                ObjectParameter stat = new ObjectParameter("status", typeof(string));
                                try
                                {
                                    var result = db.GetCurrencyRate(fromCur, toCur, Convert.ToInt64(source), apikey, stat);
                                    foreach (var s in result)
                                    {
                                        rate = s.rate;
                                    }
                                    var conversionJson = conversion.GetConvertedAmount(fromCur, toCur, rate, amount);
                                    resultJson = conversionJson;
                                }
                                catch
                                {
                                    resultJson = comm.GetErrorMessage("Some error occur");
                                }
                            }
                            else
                            {
                                resultJson = comm.GetErrorMessage("Source does not exists");
                            }
                        }
                        else
                        {
                            resultJson = comm.GetErrorMessage("Conversion rate not available");
                        }
                    }
                }
                else
                {
                    resultJson = comm.GetErrorMessage("Some parameters are missing or incorrect");
                }
            }
            return(resultJson);
        }