c# - 单例:两全其美(想实例化类)

Question

使用这段代码:

public class MyClass
{
    public int Number;

    private static MyClass myClass;

    ...

    public MyClass GetInstance()
    {
        ...

        return myClass;
    }
}

有没有一种方法可以同时支持以下两种说法？

MyClass.Number = 5;

其中 MyClass 检索用于存储 Number 值的静态类

和

MyClass myLocalClass = new MyClass();

或者脱离 Singleton 设计模式的替代方案，因为我也希望能够创建一个实例。

感谢您的关注!

Answer 1

您正在寻找的是 MonoState图案。我将引用 Robert C. Martin 的 C# 中的敏捷原则、模式和实践

The MONOSTATE pattern is another way to achieve singularity. It works through a completely different mechanism.

The first test function simply describes an object whose x variable can be set and retrieved. But the second test case shows that two instances of the same class behave as though they were one. If you set the x variable on one instance to a particular value, you can retrieve that value by getting the x variable of a different instance. It's as hough the two instances are simply different names for the same object.

因此您可以实例化 2 个或更多类，但它们都将共享相同的值。

下面是一个实现的例子:

public class Monostate
{
    private static int itsX;

    public int X
    {
        get { return itsX; }
        set { itsX = value; }
    }
}

还有测试，所以你可以看到它是如何使用的:

using NUnit.Framework;

[TestFixture]
public class TestMonostate
{
    [Test]
    public void TestInstance()
    {
        Monostate m = new Monostate();
        for (int x = 0; x < 10; x++)
        {
            m.X = x;
            Assert.AreEqual(x, m.X);
        }
    }
    [Test]
    public void TestInstancesBehaveAsOne()
    {
        Monostate m1 = new Monostate();
        Monostate m2 = new Monostate();
        for (int x = 0; x < 10; x++)
        {
            m1.X = x;
            Assert.AreEqual(x, m2.X);
        }
    }
}