C# 微信v3退款

1.退款需要退款證書。C#都是用p12的證書，雙擊證書導入，密碼是mch_id（商戶號）

2.調用微信退款接口進行退款操作

  

string  resp=string.Empty  
string cert = Server.MapPath("apiclient_cert.p12"); 
   string password = mch_id;（商戶號）
    ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);

  //這兩句特別注意

  // X509Certificate cer = new X509Certificate(cert, password);//線下發布需要添加的
     X509Certificate2 cer = new X509Certificate2(cert, password, X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.MachineKeySet);//線上發        布需要添加

   HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(url);
        webrequest.ClientCertificates.Add(cer);
        webrequest.Method = "post";
        webrequest.ContentType = "application/x-www-form-urlencoded";
        webrequest.ContentLength = xml.Length;
        HttpWebResponse response = null;
   try
        {
            StreamWriter swRequestWriter = new StreamWriter(webrequest.GetRequestStream());
            swRequestWriter.Write(xml);

            if (swRequestWriter != null)
                swRequestWriter.Close();

            response = (HttpWebResponse)webrequest.GetResponse();
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.Default))
            {
                resp = reader.ReadToEnd();
            }
        }
 catch (Exception exp)
        {
            throw exp;
        }
        finally
        {
            if (response != null)
                response.Close();
        }

分享幾個退款時遇到的問題
1、退款提示:訂單號非法
  原因：退款的訂單號錯誤導致的
2、退款時提示：基礎連接已關閉，或被意外關閉（驗證證書的問題）
  原因： 首先要通過證書請求退款的接口，其次要把下面的這行語句

 // X509Certificate cer = new X509Certificate(cert, password);//線下發布需要添加的
 修改成這樣的才可以
 X509Certificate2 cer = new X509Certificate2(cert, password, X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.MachineKeySet);//線上發        布需要添加
3、 Miss Parameters  
  原因：傳參數時，參數的名字和文檔大小寫不一致
4、每次退款，退款的訂單號不能相同，否則無法退款