如何返回特定的错误信息

Question

I have WebAPI based project. It has an API for user registration. RegistrationModel looks as below.

public class RegistrationTO
{

    [Required(ErrorMessage="Email required")]
    public string Email { get; set; }

    [Required(ErrorMessage="Name required")]
    public string Name { get; set; }

    [Required(ErrorMessage="Surname required")]
    public string Surname { get; set; }

}

API

 public string Post([FromBody]RegistrationTO model)
    {
        if (ModelState.IsValid)
        {
           //actual stuff
        }
        else
        {
          return "all * marked fields are required";
        }
    }

My requirement if model have Email as null, I should return message "email required", if Name is null then "Name required" & so on.

Yes,one patchy way would be :-

public string Post([FromBody]UserRegistrationTO model)
    {
        if (ModelState.IsValid)
        {
           //actual stuff
        }
        else
        {
          if(model.Email == null)
          return "Email required";
          else if(model.Name == null)
           return "name required"; // & so on.
        }
    }

Is there any other simple way to do this??

Answer 1

try do that:

        if (ModelState.IsValid)
        {
           // do something
        }
        else
            return "The following errors happen: \n" +
            ModelState.SelectMany(s => s.Value.Errors)
            .Select(s => s.ErrorMessage)
            .Aggregate((seed, currentValue) => seed += "\n" + currentValue);

I hope it can help you.

Answer 2

You can do this at the view itself.

For individual properties :

@Html.ValidationMessageFor(x => x.Email, null, new { @class = "text-danger" })

and for all failed validation

@if (!ViewData.ModelState.IsValid)
{
   <div class="alert alert-danger">
     @Html.ValidationSummary(false)
   </div>
}