Singleton和其他参数化的构造函数

Question

I have just made my class singleton by following simple code:

public sealed class Singleton
{
    private static Singleton instance=null;

    private Singleton()
    {
    }

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

Now, I also want to be able to set some properties using a constructor. However, I am little worried since this is my first time with singleton. I have following questions:

1. How can I have other parameterized constructor and also make sure that when a client application uses my class they get singleton.

2. Would it be a bad idea to have multiple constructor with singleton class?

3. What are there are multiple calls to the new "parameterized constructor" with different values?

Answer 1

Singletons are stateless, should not have any state in it. By looking at your problem you are looking for a Factory Pattern which can be created by Singleton. I think this link will help you factory-method-and-singleton-patterns