Dim d = 1
Dim task1 = Task.Delay(1)
Dim task2 = Task.Delay(2)
Dim task4 = Sub() d += 1 'Type of task4 is delegate sub
Dim task3 = task1.ContinueWith(task2) ' error
Dim task5 = task1.ContinueWith(Sub() d += 1) 'works
Dim task6 = task1.ContinueWith(task4) 'error
Dim task7 = task1.ContinueWith(New Action(Of Task)(task2)) 'error the "new" operator lead to Public delegate void Action<In T>(T obj);
'translated to vb.net it should be Public Delegate Sub Action(Of In T)(ByVal obj As T)
'so no new definition. Not sure what (Of In T) means
Dim task8 = task1.ContinueWith(New Action(Of Task)(Function() task2)) ' Somehow it works. Is this even the right way to do it? Why?
The first 4 rows are normal. I just set things up
Dim d = 1
Dim task1 = Task.Delay(1)
Dim task2 = Task.Delay(2)
Dim task4 = Sub() d += 1 'Type of task4 is delegate sub
What I really want to do is to create another task, say task3. And task3 will simply be task1, continue with task2
I try a bunch of different things and follow from some answer to some questions (I think I made the question, but I forget where) a long time ago.
Doing it
Dim task3 = task1.ContinueWith(task2) ' error
Simply doesn't work.
Doing it
Dim task5 = task1.ContinueWith(Sub() d += 1) 'works
surprisingly work. Even though Sub() d += 1 is just a lambda sub. Now I know, delegate, lambda sub, and action is kind of synonym to one another, and to what extend I have no idea.
However, Sub() d += 1 has nothing to do with Task. ContinueWith accept Action(of Task) right?
So I have no idea. Besides, doing it like that would only work for non await function.
Dim task6 = task1.ContinueWith(task4) 'error
That one doesn't work. Even though task5 and task6 should be the same and have same type.
Usually if we have dim someVar=5, we can put someVar anywhere we put 5. Same value, same type.
Here, we have
Dim task4 = Sub() d += 1
I can put
Dim task5 = task1.ContinueWith(Sub() d += 1) 'works
but not Dim task6 = task1.ContinueWith(task4) 'error
Now, ContinueWith accepts Action(of Task) so a natural thing to do is to create an Action(of Task) object
Dim task7 = task1.ContinueWith(New Action(Of Task)(task2))
Doesn't work.
Then finally someone suggested using
Dim task8 = task1.ContinueWith(New Action(Of Task)(Function() task2)) ' Somehow it works. Is this even the right way to do it? Why?
And it compiles. However, how the hell it works?
Basically I am calling the Action(Of Task) constructor and I am passing Function() task2 as a parameter. Why?
Where is the constructor of Action(Of Task)? I go to definition and I see
public delegate void Action<in T>(T obj);
Which is translateable to
Public Delegate Sub Action(Of In T)(ByVal obj As T)
And I have no idea what that means. I thought it should look like Public Sub New Action (of T)(something)
It doesn't even have New word in it.
And I am very confused.
Can anyone explain all these phenomena?
