微信公众号支付-Common

using System.Web;
/// <summary>
/// 公共帮助类
/// </summary>
public class Common {

    private HttpContext Context { get; set; }
    public static string OpenId = "Openid";
    public static string access_token = "access_token";

    #region 构造函数
    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="Context"></param>
    public Common(HttpContext context)
    {
        this.Context = context;
    }
    #endregion


    #region 通过code换取AccessToken
    /// <summary>
    /// 通过code换取AccessToken
    /// </summary>
    public void GetOpenidAndAccessToken()
    {
        if (!string.IsNullOrEmpty(Context.Request.QueryString["code"]))
        {
            //获取code码，以获取openid和access_token
            string code = Context.Request.QueryString["code"];
            GetOpenidAndAccessTokenFromCode(code);
        }
        else
        {
            //构造网页授权获取code的URL
            string host = Context.Request.Url.Host;
            string path = Context.Request.Path;
            string redirect_uri = HttpUtility.UrlEncode("http://" + host + path);


            WxPayData data = new WxPayData();
            data.SetValue("appid",

WxPayConfig.APPID);
            data.SetValue("redirect_uri", redirect_uri);
            data.SetValue("response_type", "code");
            data.SetValue("scope", "snsapi_base");
            data.SetValue("state", "STATE" + "#wechat_redirect");
            string url = "https://open.weixin.qq.com/connect/oauth2/authorize?" + data.ToUrl();
            try
            {
                //触发微信返回code码         
                Context.Response.Redirect(url);//Redirect函数会抛出ThreadAbortException异常，不用处理这个异常
            }
            catch (System.Threading.ThreadAbortException ex)
            {
            }
        }
    }

    #endregion

    #region 通过用户授权获取AccessToken和OpenId
    /// <summary>
    /// 通过用户授权获取AccessToken和OpenId
    /// </summary>
    /// <param name="code"></param>
    public void GetOpenidAndAccessTokenFromCode(string code)
    {
        try
        {
            //构造获取openid及access_token的url
            WxPayData data = new WxPayData();
            data.SetValue("appid",

WxPayConfig.APPID);
            data.SetValue("secret",

WxPayConfig.APPSECRET);
            data.SetValue("code",

code);
            data.SetValue("grant_type", "authorization_code");
            string url = "https://api.weixin.qq.com/sns/oauth2/access_token?" + data.ToUrl();

            //请求url以获取数据
            string result = HttpService.Get(url);

            //保存access_token，用于收货地址获取
            JsonData jd = JsonMapper.ToObject(result);
            access_token = (string)jd["access_token"];

            //获取用户openid
            OpenId = (string)jd["openid"];
        }
        catch (Exception ex)
        {
            throw new WxPayException(ex.ToString());
        }
    }
    #endregion

    #region 获取OpenId
    /// <summary>
    /// 获取OpenId
    /// </summary>
    /// <param name="postStr"></param>
    /// <returns></returns>
    public string GetOpenId()
    {
        Common common = new Common(Context);
        common.GetOpenidAndAccessToken();
        return OpenId;
    }
    #endregion



}