从其他应用程序访问Web方法获得500内部服务器错误

Question

我正在尝试使用来自MVC 4控制器的以下代码访问其他asp.net应用程序中的web方法

using (WebClient client = new ReplicateUserControl())
{
    string url = "http://localhost:1469/CMSPages/WebService.asmx/AuthWebMethod";
    //List<string> getWidgetValue = new List<string>();
    System.Collections.Specialized.NameValueCollection reqparm = new    
    System.Collections.Specialized.NameValueCollection();
    reqparm.Add("Query", "changeTheme");
    var getValue  = client.UploadValues(url, "POST", reqparm);                   
}

以下是我的其他asp.net应用程序的web方法，该方法用于加载用户控件HTML数据并将其设置在一个列表字符串中。

[WebMethod(MessageName = "AuthWebMethod")]
public byte [] AuthWebMethod(string Query)
{

    string getStringList = "";
    byte[] setValue;
    UserControl userControl;
    using (Page page = new Page())
    {
        if (!string.IsNullOrEmpty(Query))
        {

            if (Query.ToUpper() == "USERINFO")
            {
                StringBuilder sb = new StringBuilder();
                StringWriter tw = new StringWriter(sb);
                HtmlTextWriter hw = new HtmlTextWriter(tw);
                userControl = (UserControl)page.LoadControl(VirtualPathUtility.ToAbsolute("~/UserControls/Fortius.DreamTrips/UserInformation.ascx"));
                userControl.RenderControl(hw);

                getStringList += sb.ToString();


            }
            else if (Query.ToUpper() == "CHANGETHEME")
            {
                StringBuilder sb = new StringBuilder();
                StringWriter tw = new StringWriter(sb);
                HtmlTextWriter hw = new HtmlTextWriter(tw);
                userControl = (UserControl)page.LoadControl(VirtualPathUtility.ToAbsolute("~/UserControls/Fortius.DreamTrips/DreamTrips_Themes.ascx"));
                userControl.RenderControl(hw);

                getStringList += sb.ToString();
            }


        }
    }

   setValue = System.Text.Encoding.UTF8.GetBytes(getStringList);

    return setValue;
}

正如我们在这个web方法中看到的，我在列表字符串中加载用户控件HTML和脚本以及CSS。

我可以点击这个方法但是当它返回时我得到500 Internal Server Error。