fuine6/required-value-types

A clean way to use required value types in ASP.NET Core

Required Value Types

How do you deal with required value types in input models without having to make all of them nullable?

Implementation & sample controller are provided.

Read the article/tutorial here.

How to use

Copy over the RequiredValueTypes folder to your project.

Then add the following line, somewhere after any other services that change MvcOptions:

builder.Services.UseExplicitRequiredValueTypes();

Now you can use the [Required] attribute in your input models and it'll work with value types.

Sample

public record PersonInputModel
{
    [Required(ErrorMessage = "Provide an ID.")] public int Id { get; init; }
    public int? Age { get; init; }
    public string Name { get; init; } = null!;
}

public record PersonAtLocationInputModel
{
    [Required] public decimal Latitude { get; init; }
    [Required] public decimal Longitude { get; init; }
    [Required] public PersonInputModel Person { get; init; } = null!;
}

public class AppController : ControllerBase
{
    [Route("app")]
    public IActionResult App([FromBody] PersonAtLocationInputModel inputModel)
    {
        if (!ModelState.IsValid) {
            return BadRequest(ModelState);
        }

        return Ok(inputModel);
    }
}

License

MIT. See LICENSE.md.