ASP.NET Core identify give null value (identify)-CodePudding

I created a class called ApplicationUser that inherits from IdentityUser, and I use that ApplicationUser in a controller to show email address in view.

Controller code:

public IActionResult test()
{
        //var claimsIdentity = (ClaimsIdentity)User.Identity;
        //var claim = claimsIdentity.FindFirst(ClaimTypes.NameIdentifier);
        //ApplicationUser x = _db.ApplicationUser.SingleOrDefault( x=>x.Id==claim.Type);

        var userId = User.FindFirstValue(ClaimTypes.NameIdentifier);// will give the user's userId
        var userName = User.FindFirstValue(ClaimTypes.Name); // will give the user's userName
       
        // For ASP.NET Core <= 3.1
        ApplicationUser applicationUser =  _db.ApplicationUser.Find(userName);
        string userEmail = applicationUser?.Email;

        return View(applicationUser);
}

and this is view markup:

@model Store.Models.ApplicationUser

@{
    ViewData["Title"] = "test";
    Layout = "~/Views/Shared/_Layout.cshtml";
}
<h1>test</h1>

<h1>@Model.FullName</h1>

When I run the page, I get an error

Object reference not set to an instance of an object
Model.get returned null

and the ApplicationUser returns null.

CodePudding user response：

make sure your model ApplicationUser contains property of FullName ,

in the code below

ApplicationUser applicationUser =  _db.ApplicationUser.Find(userName);
string userEmail = applicationUser?.Email;

make sure you are getting an instance of applicationUser before returning it to the view.

CodePudding user response：

Your applicationUser should not be null when you pass it to the view. You can debug to see if query result from database is null.