public string getwxgzhpayrefund(){

//构造请求参数

requesthandler packagereqhandler = new requesthandler();

#region 构造请求参数

packagereqhandler.setparameter("appid", wxpayconfig.appid);//appid

packagereqhandler.setparameter("mch_id", wxpayconfig.mchid);//商户号

packagereqhandler.setparameter("nonce_str", tenpayv3util.getnoncestr());//随机串

packagereqhandler.setparameter("out_refund_no", out_refund_no);

packagereqhandler.setparameter("out_trade_no", out_trade_no);//订单号

packagereqhandler.setparameter("refund_fee", (int)(convert.todecimal(refund_fee) * 100) + "");

packagereqhandler.setparameter("total_fee", (int)(convert.todecimal(total_fee) * 100) + ""); //金额,以分为单位

packagereqhandler.setparameter("transaction_id", transaction_id);

packagereqhandler.setparameter("sign", packagereqhandler.createmd5sign("key", wxpayconfig.key));//商户api密钥(签名)

//

#endregion

//将参数转为xml字符串

string data = packagereqhandler.parsexml(); //发起post异步请求，获取返回的内容

//本地或者服务器的证书位置(证书在微信支付申请成功发来的通知邮件中)

string cert = @"d:\wshh\apiclient_cert.p12";

//私钥(在安装证书时设置)

string password = wxpayconfig.mchid;

servicepointmanager.servercertificatevalidationcallback = new remotecertificatevalidationcallback(checkvalidationresult);

//调用证书

x509certificate2 cer = new x509certificate2(cert, password, x509keystorageflags.persistkeyset | x509keystorageflags.machinekeyset);

#region 发起post请求

httpwebrequest webrequest = (httpwebrequest)httpwebrequest.create(wxpayconfig.refund_url);

webrequest.clientcertificates.add(cer);

webrequest.method = "post";

byte[] postdatabyte = encoding.utf8.getbytes(data);

webrequest.contentlength = postdatabyte.length;

stream stream;

stream = webrequest.getrequeststream();

stream.write(postdatabyte, 0, postdatabyte.length);

stream.close();

httpwebresponse httpwebresponse = (httpwebresponse)webrequest.getresponse();

streamreader streamreader = new streamreader(httpwebresponse.getresponsestream());

string responsecontent = streamreader.readtoend();

#endregion

var res = system.xml.linq.xdocument.parse(responsecontent);

string return_code = res.element("xml").element("return_code").value;

hashtable hashtable = new hashtable();

hashtable.add("return_code", return_code);

return dicresult;

}

private static bool checkvalidationresult(object sender, x509certificate certificate, x509chain chain, sslpolicyerrors errors)

{

if (errors == sslpolicyerrors.none)

return true;

return false;

}