下面code正在使用ASP.NET MVC中5项目。每次我运行C的ApplicationSignInManager级以下$ C $总是为空导致空引用异常。作为还算是一个新手，我不明白美元的的AccountController类传入的UserManager的实例构造函数C $的C调用和登录管理器。也许这正是我需要关注，但事实是我无法找到的code部分。任何人都为帮助？

要为precise异常是从HTTPost登录方法抛出。该signInManager总是空。

  VAR的结果=等待SignInManager.PasswordSignInAsync（model.UserName，model.Password，
                                     model.RememberMe，shouldLockout：假）;
 

下面是升C code

  [授权]
公共类的AccountController：控制器
{
    私人ApplicationUserManager _userManager;
    私人ApplicationSignInManager _signInManager;

    公众的AccountController（）
    {
    }

    公众的AccountController（ApplicationUserManager的UserManager，ApplicationSignInManager signInManager）
    {
        的UserManager =的UserManager;
        SignInManager = signInManager;
    }

    //
    // GET：/帐号/登录
    [使用AllowAnonymous]
    公众的ActionResult登录（字符串RETURNURL）
    {
        ViewBag.ReturnUrl = RETURNURL;
        返回查看（）;
    }


    公共ApplicationSignInManager SignInManager
    {
        得到
        {
            返回_signInManager？ 。HttpContext.GetOwinContext（）获取＆LT; ApplicationSignInManager＆GT;（）;
        }
        私人集合{_signInManager =价值; }
    }

    //
    //邮编：/帐号/登录
    [HttpPost]
    [使用AllowAnonymous]
    [ValidateAntiForgeryToken]
    公共异步任务＆LT;的ActionResult＆GT;登录（LoginViewModel型号，串RETURNURL）
    {
        如果（！ModelState.IsValid）
        {
            返回查看（模型）;
        }

        //这并不算登录失败对帐户锁定
        //启用密码失败触发帐户锁定，更改为shouldLockout：真
        VAR的结果=等待SignInManager.PasswordSignInAsync（model.UserName，model.Password，model.RememberMe，shouldLockout：假）;
        开关（结果）
        {
            案例SignInStatus.Success：
                返回RedirectToLocal（RETURNURL）;
            案例SignInStatus.LockedOut：
                返回视图（锁定）;
            案例SignInStatus.RequiresVerification：
                返回RedirectToAction（送code，新{RETURNURL = RETURNURL，了rememberMe = model.RememberMe}）;
            案例SignInStatus.Failure：
            默认：
                ModelState.AddModelError（，无效的登录尝试。）;
                返回查看（模型）;
        }
    }
 }
 

code从IdentityConfig。

  //配置应用程序登录管理器，它是用在这个应用程序。
公共类ApplicationSignInManager：SignInManager＆LT; ApplicationUser，串＆GT;
{
    公共ApplicationSignInManager（ApplicationUserManager的UserManager，IAuthenticationManager AuthenticationManager会）
        ：基地（的UserManager，AuthenticationManager会）
    {
    }

    公众覆盖任务＆LT; ClaimsIdentity＆GT; CreateUserIdentityAsync（ApplicationUser用户）
    {
        返回user.GenerateUserIdentityAsync（（ApplicationUserManager）的UserManager）;
    }

    公共静态ApplicationSignInManager创建（IdentityFactoryOptions＆LT; ApplicationSignInManager＆gt;选项，IOwinContext上下文）
    {
        返回新ApplicationSignInManager（context.GetUserManager＆LT; ApplicationUserManager＆GT;（），context.Authentication）;
    }
}
 

解决方案

检查里面的按照你的 Identity.Config.cs ：

 公共静态无效RegisterAuth（IAppBuilder应用程序）
{
    //其他code
    app.CreatePerOwinContext＆LT; ApplicationSignInManager＆GT;（ApplicationSignInManager.Create）;
    //其他code
}
 

和地方在你的项目（可能是 Startup.cs ）

  [总成：OwinStartup（typeof运算（启动），配置）
命名空间YourNamespace
{
    公共类启动
    {
        公共无效配置（IAppBuilder应用程序）
        {
            AuthConfig.RegisterAuth（应用程序）;
        }
    }
}
 

The following code is being used in ASP.NET MVC 5 project. Everytime I run the following code the ApplicationSignInManager Class always comes to be null causing null reference exception. Being fairly a newbie I don't understand what code calls in the constructor of AccountController class passing in the instance of usermanager and sign in manager. perhaps that is where I need to focus but the truth is I can't find that part of the code. Anyone up for help?

To be precise the exception is thrown from the HTTPost login method. The signInManager is always null.

var result = await SignInManager.PasswordSignInAsync(model.UserName, model.Password,
                                     model.RememberMe, shouldLockout: false);

Below is the c sharp code

[Authorize]
public class AccountController : Controller
{
    private ApplicationUserManager _userManager;
    private ApplicationSignInManager _signInManager;

    public AccountController()
    {
    }

    public AccountController(ApplicationUserManager userManager, ApplicationSignInManager signInManager)
    {
        UserManager = userManager;
        SignInManager = signInManager;
    }

    //
    // GET: /Account/Login
    [AllowAnonymous]
    public ActionResult Login(string returnUrl)
    {
        ViewBag.ReturnUrl = returnUrl;
        return View();
    }


    public ApplicationSignInManager SignInManager
    {
        get
        {
            return _signInManager ?? HttpContext.GetOwinContext().Get<ApplicationSignInManager>();
        }
        private set { _signInManager = value; }
    }

    //
    // POST: /Account/Login
    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }

        // This doesn't count login failures towards account lockout
        // To enable password failures to trigger account lockout, change to shouldLockout: true
        var result = await SignInManager.PasswordSignInAsync(model.UserName, model.Password, model.RememberMe, shouldLockout: false);
        switch (result)
        {
            case SignInStatus.Success:
                return RedirectToLocal(returnUrl);
            case SignInStatus.LockedOut:
                return View("Lockout");
            case SignInStatus.RequiresVerification:
                return RedirectToAction("SendCode", new { ReturnUrl = returnUrl, RememberMe = model.RememberMe });
            case SignInStatus.Failure:
            default:
                ModelState.AddModelError("", "Invalid login attempt.");
                return View(model);
        }
    }
 }

Code from IdentityConfig.

// Configure the application sign-in manager which is used in this application.
public class ApplicationSignInManager : SignInManager<ApplicationUser, string>
{
    public ApplicationSignInManager(ApplicationUserManager userManager, IAuthenticationManager authenticationManager)
        : base(userManager, authenticationManager)
    {
    }

    public override Task<ClaimsIdentity> CreateUserIdentityAsync(ApplicationUser user)
    {
        return user.GenerateUserIdentityAsync((ApplicationUserManager)UserManager);
    }

    public static ApplicationSignInManager Create(IdentityFactoryOptions<ApplicationSignInManager> options, IOwinContext context)
    {
        return new ApplicationSignInManager(context.GetUserManager<ApplicationUserManager>(), context.Authentication);
    }
}

Check for the following inside your Identity.Config.cs:

public static void RegisterAuth(IAppBuilder app)
{
    // other code
    app.CreatePerOwinContext<ApplicationSignInManager>(ApplicationSignInManager.Create);
    // other code
}

and somewhere in your project (possibly Startup.cs)

[assembly: OwinStartup(typeof(Startup), "Configuration")]    
namespace YourNamespace
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            AuthConfig.RegisterAuth(app);
        }
    }
}