Bearbeitung von Fragen

MultipleChoiceTrainer/Validation/NotNullOrEmptyAttribute.cs

@@ -0,0 +1,28 @@
+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;
+        }
+    }
+}