Lazy Singleton C#

Question

Lazy:

public sealed class Singleton { private static readonly Lazy<Singleton> lazy = new Lazy<Singleton> (() => new Singleton()); public static Singleton Instance { get { return lazy.Value; } } private Singleton() { } }

Form:

 private static FrmConfig _defaultInstance;
        public static FrmConfig Instance
        {
            get
            {
                if (_defaultInstance == null || _defaultInstance.IsDisposed)
                {
                    _defaultInstance = new FrmConfig();
                }
                return _defaultInstance;
            }
            set => _defaultInstance = value;
        }

Answer 1

private static readonly Lazy<DanhmucchungRepository> lazy = new Lazy<DanhmucchungRepository>(() => new DanhmucchungRepository()); 
        public static DanhmucchungRepository Instance { get { return lazy.Value; } } 
        private DanhmucchungRepository() { }