csharp EF CRUD

Posted 2021-05-12

  public static class Crud
    {
        public static int Save<T>(this T entity, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            if (entity == null)
                throw new ArgumentNullException("entity", "Die Entität darf nicht null sein");

            return Exists(entity, "Id", ctx) ? Update(entity, ctx) : Insert(entity, ctx);
        }
        public static int Insert<T>(this T entity, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            int result;
            Add(entity, ctx, out result);

            return result;
        }
        public static int Update<T>(this T entity, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            int result;
            Change(entity, ctx, out result);
            return result;
        }
        public static IQueryable<T> Get<T>(Expression<Func<T, bool>> predicate, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            return ctx.Set<T>().Where(predicate);
        }

        public static int Delete<T>(this T entity, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            ctx.Set<T>().Remove(entity);
            return ctx.SaveChanges();
        }

        private static void Add<T>(T entity, ZeiterfassungsContext ctx, out int result) where T : class, ICrud
        {
            using (var scope = new TransactionScope())
            {
                ctx.Set<T>().Add(entity);
                ctx.SaveChanges();

                result = (int)GetPropertyValue(entity, "Id");
                scope.Complete();
            }
        }
        private static void Change<T>(T entity, ZeiterfassungsContext ctx, out int result) where T : class, ICrud
        {
            var currentEntity = ctx.Set<T>().Find(GetPropertyValue(entity, "Id"));
            ctx.Entry(currentEntity).CurrentValues.SetValues(entity);

            using (var scope = new TransactionScope())
            {
                ctx.SaveChanges();
                result = (int)GetPropertyValue(entity, "Id");
                scope.Complete();
            }
        }
        private static bool Exists<T>(T entity, string propertyname, ZeiterfassungsContext ctx) where T : class, ICrud
        {
            return ctx.Set<T>().Find(GetPropertyValue(entity, propertyname)) != null;
        }

        private static object GetPropertyValue<T>(T entity, string prop)
        {
            PropertyInfo info = entity.GetType().GetProperty(prop);
            return info.GetValue(entity, null);
        }
    }