Using singleton instead of a global static instance
- by Farstucker
I ran into a problem today and a friend recommended I use a global static instance or more elegantly a singleton pattern. I spent a few hours reading about singletons but a few things still escape me.
Background:
What Im trying to accomplish is creating an instance of an API and use this one instance in all my classes (as opposed to making a new connection, etc).
There seems to be about 100 ways of creating a singleton but with some help from yoda I found some thread safe examples. ..so given the following code:
public sealed class Singleton
{
public static Singleton Instance { get; private set; }
private Singleton()
{
APIClass api = new APIClass(); //Can this be done?
}
static Singleton() { Instance = new Singleton(); }
}
How/Where would you instantiate the this new class and how should it be called from a separate class?
EDIT:
I realize the Singleton class can be called with something like
Singleton obj1 = Singleton.Instance();
but would I be able to access the methods within the APIs Class (ie. obj1.Start)? (not that I need to, just asking)
EDIT #2: I might have been a bit premature in checking the answer but I do have one small thing that is still causing me problems. The API is launching just fine, unfortunately Im able to launch two instances?
New Code
public sealed class SingletonAPI
{
public static SingletonAPI Instance { get; private set; }
private SingletonAPI() {}
static SingletonAPI() { Instance = new SingletonAPI(); }
// API method:
public void Start() { API myAPI = new API();}
}
but if I try to do something like this...
SingletonAPI api = SingletonAPI.Instance;
api.Start();
SingletonAPI api2 = SingletonAPI.Instance; // This was just for testing.
api2.Start();
I get an error saying that I cannot start more than one instance.
