[英]Is this Singleton implementation correct and thread-safe?
Is this singleton implementation correct and thread-safe? 这个单例实现是否正确且是线程安全的?
class Class
{
public static readonly Class Instance;
static Class()
{
Instance = new Class();
}
private Class() {}
}
Technically, your version should work. 从技术上讲,您的版本应该可行。 However, I would not recommend exposing a public field within your Singleton class, and prefer using a Property (with a getter only).
但是,我不建议在Singleton类中公开公共字段,而是更喜欢使用Property(仅使用getter)。 This will help future-proof your API if you need to make changes later.
如果您以后需要进行更改,这将有助于您的API未来发展。 I also recommend sealing any singleton implementation, as subclassing a singleton class is almost always a bad idea and problematic.
我还建议密封任何单例实现,因为子类化单例类几乎总是一个坏主意并且有问题。
I would, personally, use the following in C#, if you're targetting .NET 3.5 or earlier: 如果您的目标是.NET 3.5或更早版本,我个人会在C#中使用以下内容:
public sealed class Singleton
{
static readonly Singleton instance = new Singleton();
public static Singleton Instance
{
get
{
return instance;
}
}
static Singleton() { }
private Singleton() { }
}
If you're using .NET 4, you can make this even easier for yourself via Lazy<T>
: 如果你使用的是.NET 4,你可以通过
Lazy<T>
让自己变得更容易:
public sealed class Singleton
{
private static readonly Lazy<Singleton> instance = new Lazy<Singleton>( () => new Singleton() );
private Singleton() {}
public static Singleton Instance { get { return instance.Value; } }
}
The .NET 4 version also has the advantage of being fully lazy - even if your Singleton
class has other static methods which are used prior to the access of the "Instance" property. .NET 4版本还具有完全延迟的优点 - 即使您的
Singleton
类具有在访问“Instance”属性之前使用的其他静态方法。 You can do a fully-lazy .NET 3.5- version, as well, by using a private, nested class. 您也可以使用私有的嵌套类来完成一个完全懒惰的.NET 3.5版本。 Jon Skeet demonstrated this on his blog .
Jon Skeet在他的博客上证明了这一点 。
Yes. 是。 I would also make the class '
sealed
' to avoid any future confusion. 我也会让课程“
sealed
”以避免将来出现任何混淆。
Good discussion of how to do that is here: 关于如何做到这一点的好讨论在这里:
http://www.yoda.arachsys.com/csharp/singleton.html http://www.yoda.arachsys.com/csharp/singleton.html
您应该在变量声明中进行初始化:
public static readonly Class Instance = new Class();
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