我需要有关应用程序问题的帮助。使用MVC 4（newdev） [英] I need help with an application issue. Using MVC 4 (newdev)

问题描述

登录模型

Login Model

namespace jury_service.Models
{
    public class LoginModel
    {
        [Display(Name = "Username")]
        [Required]
        public string username { get; set; }


        [Display(Name = "Password")]
        [Required]
        public string Password { get; set; }
        //protected readonly WebClient Client;

        //public LoginModel(WebClient client)
        //{
        //    Client = client;
        //}
        public FCC_Users infoModel;

        public FCC_Users info;

        public List<FCC_Users> infos;

        public bool DoLogin(LoginModel login)
        {
             var ffcuser = GetInfoREcordByName(login.username);

            //Check if user model pulled back from API is null
             if (ffcuser != null)
             {
                 //if not null check to see if it has a password/intial value of '1'...
                 if (!String.IsNullOrEmpty(ffcuser.Secret))
                 {
                         if (ffcuser.Secret == login.Password)
                         {                   
                             //Check if user login is initial login...
                            if (ffcuser.Initial.Equals(1))
                            {
                                 return true;
                            }
                     }

                 }
                 else

                 {
                     return false;
                 }
             }

             return false;
        }

        //public bool DoLogin()
        //{
        //    if (Initial == "1" && Password != "null")
        //    {
        //        return true;
        //    }

        //    return false;
        //}

        //public User GetUser(LoginModel login)
        //{
        //    try
        //    {
        //        //Add Request Headers
        //        Client.Headers.Add(HttpRequestHeader.ContentType, "application/json");
        //        //Make Request to API and return results
        //        return JsonConvert.DeserializeObject<User>(Client.DownloadString(new Uri(Properties.Settings.Default.Api_Url + "Info" + "/?username=" + login.username + "/")));
        //    }
        //    catch (Exception ex)
        //    {
        //        return null;
        //    }
        //}
        public FCC_Users GetInfoREcordByName(string infoName)
        {
            WebClient client = new WebClient();
            string url = Properties.Settings.Default.Api_Url + "Info/?infoName=" + infoName;
            info = JsonConvert.DeserializeObject<FCC_Users>(client.DownloadString(url));
            return info;
        }
        public FCC_Users GetAllInfoRecords(string infoName)
        {
            WebClient client = new WebClient();
            string url = Properties.Settings.Default.Api_Url + "Info";
            infos = JsonConvert.DeserializeObject<List<FCC_Users>>(client.DownloadString(url));
            return infos.Where(x => x.Username == infoName).First()
        }

    }
}

登录控制器

Login Controller

namespace jury_service.Controllers
{
    public class FCCLoginController : Controller
    {
        //private FCC_Users username;
        //
        // GET: /FCCLogin/

        public ActionResult Index()
        {
            return View();
        }


        [HttpPost]
        public ActionResult Index(LoginModel login)
        {
            if (ModelState.IsValid)
            {

                var ffcuser = login.GetAllInfoRecords(login.username);
                //Check to see if user exists...
                if (ffcuser != null)
                {
                //If user exists, check password matches...

                //If password matches, check if initial login...
                      if (!String.IsNullOrEmpty(ffcuser.Secret))
                        {

                         if (ffcuser.Secret == login.Password)
                         {                   
                             //Check if user login is initial login...
                            if (ffcuser.Initial)
                            {
                             return RedirectToAction("CreatePassword", "Newpassword");
                            }
                            //else
                            // if (ffcuser != username)
                                {
                                    ModelState.AddModelError("Error", "Wrong Username and/or Password");
                                    //ModelState.Clear();
                                }

                                    
                }
                      }
                    return RedirectToAction("fccindex", "FCCLogin");
               
                }
                 

            }

            return View();
        }

        public ActionResult fccindex()
        {
            return View();

        }

我的尝试：



我尝试登录验证。如果用户名和&密码是正确的而不是错误，但如果不正确，则会在此处发生错误.First



返回infos.Where（x => x.Username == infoName）。第一个（）;

What I have tried:

My attempt at a login authentication. If username & password is correct not error, but if incorrect the error happens in here at .First

return infos.Where(x => x.Username == infoName).First();

推荐答案

我想因为它没有找到任何结果，所以它是null并且发生异常。



参考 - Enumerable.First（TSource）方法（IEnumerable（ TSource））（System.Linq） [ ^ ]

I guess as it is not finding any result, so it is null and exception happens.

Refer - Enumerable.First(TSource) Method (IEnumerable(TSource)) (System.Linq)[^]

引用：

首先< TSource > （IEnumerable < TSource > ）如果 source 不包含任何元素， 方法将引发异常。要在源序列为空时返回默认值，请使用 FirstOrDefault 方法。

The First<TSource>(IEnumerable<TSource>) method throws an exception if source contains no elements. To instead return a default value when the source sequence is empty, use the FirstOrDefault method.

你应该使用FirstOrDefault。

You should user FirstOrDefault.

删除这个

return infos.Where(x => x.Username == infoName).First()

add

add

return infos.FirstOrDefault(x => x.Username == infoName);

make确定您要验证空值。

make sure you are validating for null values.

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