using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; using System.Linq; using System.Threading.Tasks; namespace MultipleChoiceTrainer.Validation { public class NotNullOrEmptyAttribute : ValidationAttribute { public NotNullOrEmptyAttribute() { } protected override ValidationResult IsValid(object value, ValidationContext validationContext) { if (value == null) return new ValidationResult($"{validationContext.DisplayName} darf nicht leer sein!"); if (string.IsNullOrEmpty(value.ToString()) || string.IsNullOrWhiteSpace(value.ToString())) { return new ValidationResult($"{validationContext.DisplayName} darf nicht leer sein!"); } return ValidationResult.Success; } } }