C# 獲取微信小程序access_token

/// <summary>
/// 獲取access_token
/// </summary>
/// <returns></returns>
public static string GetAccessToken()
{
    string token = string.Empty;
    try
    {
        # 微信小程序接口
        string wechatapi = ConfigurationManager.AppSettings["wechatapi"].ToString();
        string appID = ConfigurationManager.AppSettings["AppID"].ToString();
        string appSecret = ConfigurationManager.AppSettings["AppSecret"].ToString();
        //獲取微信token
        string token_url = "cgi-bin/token?grant_type=client_credential&appid=" + appID + "&secret=" + appSecret;

        var operateResult = LzWebAPICaller.Get<obxxxxject>(wechatapi token_url).ToString();
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(token_url);
        //請求方式
        myRequest.Method = "GET";
        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        StreamReader reader = new StreamReader(myResponse.GetResponseStream() Encoding.UTF8);
        string content = reader.ReadToEnd();
        myResponse.Close();
        reader.Dispose();
        javascriptSerializer serializer = new javascriptSerializer();
        token = serializer.Deserialize<string>(content);


    }
    catch (Exception ex)
    {
        token = "";
        ExceptionPolicy.HandleException(ex LZExceptionType.System
          "獲取token失敗!源:Lz.Product.LJXQJGF.BLL.Resident.ResidentLogic.GetAccessToken方法出錯 ");
    }
    return token;
}