问题:

I could not find a direct answer to this question yet in SO. Is there a predefined delegate with void (void) signature?

回答1:

Action has the signature you're looking for. However, it doesn't mean the same thing as Runnable does: Runnable generally indicates that the run() method is intended to be run on a Thread, while Action makes no indication. For that you'd want ThreadStart, which has the same signature, and does make that indication.

If all you need is a delegate with no parameters, Action is what you want. If you're dealing with threads and need to indicate the start method, use ThreadStart.

回答2:

Nope. C# handles threads differently to Java. In Java, the Runnable interface is an alternative to subclassing Thread, but you still have to create a new Thread object, passing the Runnable to a constructor.

Rather than subclassing the Thread class, you simply create a new System.Threading.Thread object and pass it a ThreadStart delegate (this is the function where you do the work). ThreadStart is the exact C# equivalent to Java's Runnable.

However, the Action delegate has the void parameters you speak of.