ASP.NET Core 3 and React

Adding validation to posting an answer

Let's add validation to the request for posting an answer:

1. Open AnswerPostRequest.cs and add the following using statement:

using System.ComponentModel.DataAnnotations;

2. Add the following validation attributes and make QuestionId nullable:

public class AnswerPostRequest{    [Required]    public int? QuestionId { get; set; }    [Required]    public string Content { get; set; }    ...}

So, we require the QuestionId to be supplied along with the answer content.

Notice the ? after the int type on the QuestionId property.

The ? allows the property to have a null value as well as the declared type. T? is shortcut syntax for Nullable<T>.

So, why does QuestionId need to be able to hold a null value? This is because an ...