c# - Array must contain 1 element

Question

I have the following class:

public class CreateJob
{
    [Required]
    public int JobTypeId { get; set; }
    public string RequestedBy { get; set; }
    public JobTask[] TaskDescriptions { get; set; }
}

I'd like to have a data annotation above TaskDescriptions so that the array must contain at least one element? Much like [Required]. Is this possible?

question from:https://stackoverflow.com/questions/13361500/array-must-contain-1-element

Answer 1

I've seen a custom validation attribute used for this before, like this:

(I've given sample with a list but could be adapted for array or you could use list)

public class MustHaveOneElementAttribute : ValidationAttribute
{
    public override bool IsValid(object value)
    {
        var list = value as IList;
        if (list != null)
        {
            return list.Count > 0;
        }
        return false;
    }
}
[MustHaveOneElementAttribute (ErrorMessage = "At least a task is required")]
public List<Person> TaskDescriptions { get; private set; }