/// <summary>
/// 申请退款
/// </summary>
/// <param name="transactionId">微信支付交易号</param>
/// <param name="outRefundNo">商户系统内部的退款单号，商户系统内部唯一，同一退款单号多次请求只退一笔</param>
/// <returns></returns>
public async Task <RefundResponse> RefundAsync(string transactionId, string outRefundNo, decimal totalFee, decimal refundFee)
{
// var appEnv = _commonContext.GetService<IApplicationEnvironment>();
var clientService = new ClientService(_loggerFactory);
var refundReq = new RefundRequest(_weixinSetting);
refundReq.transaction_id = transactionId;
refundReq.out_refund_no = outRefundNo;
refundReq.total_fee = refundReq.ConverDecimalToIntMoney(totalFee);
refundReq.refund_fee = refundReq.ConverDecimalToIntMoney(refundFee);
refundReq.nonce_str = Utility.GenerateNonceStr();
refundReq.sign = Utility.MakeSign(refundReq, _weixinSetting.PartnerKey);
var resp = await clientService.ExecuteAsync(
refundReq,
RequestStringDataTypes.Xml,
_weixinSetting.CertPassword,
_weixinSetting.CertFullName);
return(resp);
}