c#微信支付v2

	openid:用户openId
	outTradeNo：订单编号
	description：商品描述
	totalFee：金额
	public string UnifiedOrder(string openid, string outTradeNo, string description, int totalFee)
    {
        // 构造请求参数
        SortedDictionary<string, object> parameters = new SortedDictionary<string, object>();
        parameters.Add("appid", appId);
        parameters.Add("mch_id", mchId);
        parameters.Add("nonce_str", GetNonceStr());
        parameters.Add("body", description);
        parameters.Add("out_trade_no", outTradeNo);
        parameters.Add("total_fee", totalFee.ToString());
        parameters.Add("spbill_create_ip", "127.0.0.1");
        parameters.Add("notify_url", notifyUrl);
        parameters.Add("trade_type", "JSAPI");
        parameters.Add("openid", openid);

        // 签名
        string sign = CreateSign(parameters, AES_KEYV2);
        parameters.Add("sign", sign);

        // 转换为XML格式
        string xml = DictionaryToXml(parameters);

        // 发送POST请求到微信支付服务器
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://api.mch.weixin.qq.com/pay/unifiedorder");
        request.Method = "POST";
        request.ContentType = "text/xml";
        byte[] data = Encoding.UTF8.GetBytes(xml);
        request.ContentLength = data.Length;
        Stream stream = request.GetRequestStream();
        stream.Write(data, 0, data.Length);
        stream.Close();

        // 获取响应
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
        string result = reader.ReadToEnd();
        reader.Close();
        response.Close();

        // 解析XML格式的响应
        XmlDocument doc = new XmlDocument();
        doc.LoadXml(result);
        XmlNode rootNode = doc.SelectSingleNode("xml");
        string returnCode = rootNode.SelectSingleNode("return_code").InnerText;
        string resultCode = rootNode.SelectSingleNode("result_code").InnerText;
        if (returnCode == "SUCCESS" && resultCode == "SUCCESS")
        {
            // 生成JSAPI支付参数
            SortedDictionary<string, object> jsApiParameters = new SortedDictionary<string, object>();
            jsApiParameters.Add("appId", appId);
            jsApiParameters.Add("timeStamp", GetTimestamp());
            jsApiParameters.Add("nonceStr", GetNonceStr());
            jsApiParameters.Add("package", "prepay_id=" + rootNode.SelectSingleNode("prepay_id").InnerText);
            jsApiParameters.Add("signType", "MD5");

            // 签名
            string jsApiSign = CreateSign(jsApiParameters, AES_KEYV2);
            jsApiParameters.Add("paySign", jsApiSign);
            // 转换为JSON格式并返回
            return DictionaryToJson(jsApiParameters);
        }
        else
        {
            throw new Exception(rootNode.SelectSingleNode("err_code_des").InnerText);
        }
    }
	
    // 创建签名
    private string CreateSign(SortedDictionary<string, object> parameters, string key)
    {
        StringBuilder sb = new StringBuilder();
        foreach (KeyValuePair<string, object> pair in parameters)
        {
            if (!string.IsNullOrEmpty(pair.Value.ToString()))
            {
                sb.Append(pair.Key + "=" + pair.Value + "&");
            }
        }
        sb.Append("key=" + key);
        return GetMd5(sb.ToString()).ToUpper();
    }
	
    // 获取MD5哈希值
    private string GetMd5(string str)
    {
        MD5 md5 = new MD5CryptoServiceProvider();
        byte[] data = Encoding.UTF8.GetBytes(str);
        byte[] hash = md5.ComputeHash(data);
        StringBuilder sb = new StringBuilder();
        foreach (byte b in hash)
        {
            sb.Append(b.ToString("x2"));
        }
        return sb.ToString();
    }
	
    // 获取随机字符串
    private string GetNonceStr()
    {
        Random random = new Random();
        return GetMd5(random.Next(1000).ToString());
    }

    // 获取时间戳
    private string GetTimestamp()
    {
        TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
        return Convert.ToInt64(ts.TotalSeconds).ToString();
    }
	
    // 将字典转换为XML格式
    private string DictionaryToXml(SortedDictionary<string, object> dictionary)
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("<xml>");
        foreach (KeyValuePair<string, object> pair in dictionary)
        {
            if (!string.IsNullOrEmpty(pair.Value.ToString()))
            {
                sb.Append("<" + pair.Key + ">" + "<![CDATA[" + pair.Value + "]]></" + pair.Key + ">");
            }
        }
        sb.Append("</xml>");
        return sb.ToString();
    }
	
    // 将字典转换为JSON格式
    private string DictionaryToJson(SortedDictionary<string, object> dictionary)
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("{");
        foreach (KeyValuePair<string, object> pair in dictionary)
        {
            if (!string.IsNullOrEmpty(pair.Value.ToString()))
            {
                sb.Append("\"" + pair.Key + "\":\"" + pair.Value + "\",");
            }
        }
        sb.Remove(sb.Length - 1, 1);
        sb.Append("}");
        return sb.ToString();
    }
	
	
	
	其中 appId 微信appId，mchId商户号，notifyUrl回调地址，AES_KEYV2：v2秘钥
	
	
	//前端js
	
	var local = encodeURIComponent(window.location.href);
	var appid = $("#appId").text();
	var url = 'https://open.weixin.qq.com/connect/oauth2/authorize?appid=' + appid + '&redirect_uri=' + 		local + '&response_type=code&scope=snsapi_base&state=STATE#wechat_redirect';
	window.location.href = url;
	
	var url ="Wechat/Pay?code=" + code;
    $.ajax({
        type: "GET",
        url: url,
        contentType: "application/x-www-form-urlencoded",
        success: function (res) {
            if (res.code == "1") {
                var response = res.data;
                WeixinJSBridge.invoke(
                    'getBrandWCPayRequest', {
                    "appId": response.appId,     //公众号ID，由商户传入     
                    "timeStamp": response.timeStamp,         //时间戳，自1970年以来的秒数     
                    "nonceStr": response.nonceStr, //随机串     
                    "package": response.package,
                    "signType": response.signType,         //微信签名方式：     
                    "paySign": response.paySign//微信签名 
                }, function (res) {
                    if (res.err_msg == "get_brand_wcpay_request:cancel") {
                        hintIfno("支付已经取消");
                        return false;
                    } else if (res.err_msg == "get_brand_wcpay_request:ok") {
                        hintIfno("支付成功");
                    } else {
                        hintIfno("支付失败，请返回列表页重新支付");
                    }
                });
            } else {
            }
        }
    });