public class WeCharBase
  {
    private static readonly string appId;
    private static readonly string appSecret;

    static WeCharBase()
    {
      appId = "**********";
      appSecret = "832090bfddabbac19cc8da5053aea47b";
    }

    public static string AccessToken
    {
      get { return GetAccessToken(); }
    }

    /// <summary>获取access_token</summary>
    /// <param name="appId"></param>
    /// <param name="appSecret"></param>
    /// <returns></returns>
    private static string GetAccessToken()
    {
      if (HttpContext.Current == null)
      {
        return GetToken();
      }

      var accessTokenCache = HttpContext.Current.Cache["access_token"];
      if (accessTokenCache != null)
      {
        return accessTokenCache.ToString();
      }
      else
      {
        return GetToken();
      }
    }

    /// <summary>获取ccess_token</summary>
    /// <returns></returns>
    private static string GetToken()
    {
      try
      {
        var client = new WebClient();
        client.Encoding = Encoding.UTF8;
        var responseData = client.DownloadString(string.Format("https://api.weixin.qq.com/cgi-bin/token", appId, appSecret));

        var javaScriptSerializer = new JavaScriptSerializer();
        var accessDictionary = javaScriptSerializer.Deserialize<Dictionary<string, object(responseData);
        var accessToken = accessDictionary["access_token"];
        if (accessToken == null)
        {
          return string.Empty;
        }

        HttpContext.Current.Cache.Insert("access_token", accessToken, null, DateTime.Now.AddSeconds(7100), TimeSpan.Zero, CacheItemPriority.Normal, null);
        HttpContext.Current.Cache.Remove("ticket");
        GetTicket();

        return accessToken.ToString();
      }
      catch (Exception ex)
      {
        return ex.Message;
      }
    }
  }

/// <summary>获取AccessToken</summary>
    /// <returns></returns>
    public ActionResult ViewAccessToken()
    {
      return View();
    }
    /// <summary>获取AccessToken</summary>
    /// <returns></returns>
    public ActionResult GetAccessToken()
    {
      return Content(WeCharBase.AccessToken);
    }

<script type="text/javascript" language="javascript">
  $(document).ready(function () {
    $("#btnGetAccessToken").click(function () {
      $.ajax({
        type: "Get",
        url: "/Subscript/GetAccessToken",
        success: function (responseTest) {
          $("#txtAccessToken").text(responseTest);
        }
      });
    });
  });
</script>

<table>
  <tr>
    <td>
      <div class="title">获取access token</div>
      <textarea id="txtAccessToken" name="txtAccessToken" rows="4" style="width:500px"></textarea>
    </td>
    <td><input class="btncss" id="btnGetAccessToken" type="button" value=" 获取 " /></td>
  </tr>
</table>