public long Add(Vendor obj)
        {
            if (IsDuplicate(obj.VendorCode, obj.Id, obj.CustomerId) == false)
            {
                return(_vendorRepository.Add(obj));
            }
            else
            {
                Expression <Func <Vendor, bool> > res = x => x.VendorCode == obj.VendorCode && x.CustomerId == obj.CustomerId && x.IsActive == false;
                var model = _vendorRepository.Get(res);

                if (model != null)
                {
                    obj.Id       = model.Id;
                    obj.IsActive = true;

                    _vendorRepository.Detach(model);

                    _vendorRepository.Update(obj);

                    return(obj.Id);
                }
                else
                {
                    return(0);
                }
            }
        }