Unit of Work example. Shows a single control class that will house a single context and all relevant repositories using the generic repository pattern

UnitOfWork.cs

using System;

namespace mycompany.employee_manager.Core.Data.Repository
{
    public class UnitOfWork : IDisposable
    {
        #region -- Fields --
        private readonly MyContext _context = new MyContext();
        private GenericRepository<User> _userRepository;
        private GenericRepository<Department> _departmentRepository; 
        #endregion

        #region -- Repositories --
        public GenericRepository<User> UserRepository
        {
            get { return _userRepository ?? (_userRepository = new GenericRepository<User>(_context)); }
        }

        public GenericRepository<Department> DepartmentRepository
        {
            get
            {
                return _departmentRepository ??
                       (_departmentRepository = new GenericRepository<Department>(_context));
            }
        } 
        #endregion

        #region -- IDisposable --
        private bool _disposed = false;

        protected virtual void Dispose(bool disposing)
        {
            if (!_disposed)
            {
                if (disposing)
                {
                    _context.Dispose();
                }
            }
            _disposed = true;
        }
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        #endregion 
    }
}