question

I assume you properly registered the services by calling AddDefaultIdentity at app startup correct?

Personally I wouldn't recommend that you pass IdentityUser as data to the model. There is way more information in that object than you should need in your view. The data is already available in the Controller class so you should ideally either wrap the user information into its own model (if you need several pieces of data) or just expose the user's display name, email or something. This would completely solve the issue while not exposing more sensitive data.

The user's identity is cached in an authentication cookie and the Identity middleware exposes the user principal within an HTTP request. For example the following gets the username in the Get or Post Razor Page methods.

 User.Identity.Name

Typically you don't want to expose the user information to the browser. When a user creates a blog entry you'll simply grab the user's Id and use the Id to relate the record to the user.

 var user = await _userManager.GetUserAsync(User);
 var userId = user.Id;

The same idea applies to fetching records. Fetch the current user's identity (id) and use the Id to filter the records so only the logged in user can see their information.

Lastly, using entities to scaffold Razor pages in not always a good idea. For example, you do not want to expose the user's Id to the browser. An entity will have the user's Id so rather than scaffolding an entity scaffold a view model. Use the view model to populate an entity to do any CRUD operations.

Hi @daniel-niccoli,

No suitable constructor was found for entity type 'BlogPost'. The following constructors had parameters that could not be bound to properties of the entity type: cannot bind 'author' in 'BlogPost(IdentityUser author, string title, string content)'.

To solve this issue, you could add a parameterless constructor on the BlogPost class, like this:

 public class BlogPost
 {
     public string Id { get; set; }
     [Required]
     public IdentityUser Author { get; set; }
     [Required]
     public string Title { get; set; }
     [Required]
     public string Content { get; set; }
     [Required]
     public DateTime CreationDate { get; set; }
    
     public BlogPost()  {   }

     public BlogPost(IdentityUser author, string title, string content)
     {
         Author = author;
         Title = title;
         Content = content;
         CreationDate = DateTime.UtcNow;
     }
 }

Then, enable migrations, it should works well.

Note: when adding a new item to the BlogPost table, you need to set the Author, otherwise it will show the foreign key (AuthorId) is null exception, like this:

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Best regards,
Dillion