vb.net - vb中的单例模式

Question

我通常是C＃程序员，但现在在VB中为这个项目工作，当我用来设置单例类时，我将遵循Jon Skeet模型

public sealed class Singleton
{
    static Singleton instance = null;
    static readonly object padlock = new object();

    Singleton()
    {
    }

    public static Singleton Instance
    {
        get
        {
            lock (padlock)
            {
                if (instance == null)
                {
                    instance = new Singleton();
                }
                return instance;
            }
        }
    }

    //Added to illustrate the point
    public static void a()
    {
    }

    public void b()
    {
    }

} 

或现在的一种变体，如果我用C＃编写语句

Singleton.Instance哪些程序不是b，但不是a的所有静态成员。

现在，当我在VB中执行相同操作时

Private Shared _instance As StackTracker
Private Shared ReadOnly _lock As Object = New Object()
Private Sub New()
    _WorkingStack = New Stack(Of MethodObject)
    _HistoryStack = New Queue(Of MethodObject)
End Sub

Public Shared ReadOnly Property Instance() As StackTracker
    Get
        SyncLock _lock
            If (_instance Is Nothing) Then
                _instance = New StackTracker()
            End If
        End SyncLock

        Return _instance
    End Get

End Property

我得到StackTracker.Instance.Instance并且它继续前进，虽然这不是世界末日，但它看起来很糟糕。

问题在VB中是否有隐藏第二个实例的方法，以便用户无法递归调用Instance？

Answer 1

这是完整的代码：

Public NotInheritable Class MySingleton
    Private Shared ReadOnly _instance As New Lazy(Of MySingleton)(Function() New
        MySingleton(), System.Threading.LazyThreadSafetyMode.ExecutionAndPublication)

    Private Sub New()
    End Sub

    Public Shared ReadOnly Property Instance() As MySingleton
        Get
            Return _instance.Value
        End Get
    End Property
End Class

然后使用此类，使用以下方法获取实例：

Dim theSingleton As MySingleton = MySingleton.Instance