Wsrtjtyk

After reviewing several articles and SO questions, I still cannot understand why my validation attributes are not triggering.

For simplicity, I have reduced my model and added the string testing to debug.

using System;

using System.ComponentModel.DataAnnotations;



namespace PublicApi

{

  public class CostStandardRequest

  {

    [DateLessThan("EndDate", ErrorMessage = "StartDate must be less than EndDate")]

    public DateTime StartDate { get; set; }

    public DateTime EndDate { get; set; }



    [Required]

    public string testing { get; set; }

  }

}

In my controller, I test my method by passing a null value to the testing attribute in my CostStandardRequest class. However, ModelState.IsValid returns true despite null values.:

[HttpPost]

public async Task<ActionResult<string>> PostCostingStandard(CostStandardRequest request)

{

  if (ModelState.IsValid)

  {

    // always valid

  }

  else

  {

    // never runs

  }

}

I've reached this point by following the guide in the documentation

Note: ModelState.IsValid is true even when my custom validation attribute [DateLessThan] should be returning a ValidationResult(ErrorMessage). I have not included this code, but I can if it's deemed relevant.