Difference between ThreadStart and Action

Question

Does someone know the difference between

Dispatcher.BeginInvoke(DispatcherPriority.Background, new ThreadStart(() =>
{

and

Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
{

Answer 1

There should be no difference. ThreadStart and Action are defined as

public delegate void ThreadStart();

public delegate void Action();

i.e., delegate with no parameters and no return value. So they are semantically the same.

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However, I would use Action and not ThreadStart, as ThreadStart is strongly associated with Thread constructor, so the code with ThreadStart can hint to direct thread creation and therefore be slightly misleading.

Answer 2

It looks like there is a difference between ThreadStart and Action in the context of BeginInvoke.

They will both run the code within the delegate correctly, as Vlad has mentioned.

However, if an exception occurs within the delegate, ThreadStart results in a TargetInvocationException. But using Action gives you the correct exception from the delegate.

Action should be preferred for this reason.

Have a look at this question.