School/SchoolProject/EmployeePartial.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SchoolProject
{
    public partial class Employee
    {
        public string FullName
        {
            get
            {
                return $"{LastName} {Name[0]}. {MiddleName[0]}.";
            }
        }

        public int Age
        {
            get
            {
                double Age = (DateTime.Today - BirthDate).Days / 365;
                return Convert.ToInt32(Math.Truncate(Age));
            }
        }
        public string IsWorkingString
        {
            get
            {
                return IsWorking ? "Работает" : "Уволен";
            }

        }

     }
}