Await / async - async method runs in Main Thread - multithreading

Question

I just started to learn Async/Await, and I've got a problem. There is a WinForms App with 2 buttons and permanently running status-bar on it. When pressing first button - everithing is fine - cicle running in another thread and UI doesn't freeze. When pressing second - cicle running in Main Thread, so UI freeze. I just can't get it! Why? For me this methods look almost the same. Btw sry my bad english.
Public Class Form1
'Async - Create Task from Sync Method
Private Async Sub btn_async_from_sync_Click(sender As Object, e As EventArgs) Handles btn_async_from_sync.Click
Dim tsk As New Task(Of Integer)(AddressOf func_for_task)
tsk.Start()
Dim val As Integer = Await tsk
MsgBox(val)
End Sub
Private Function func_for_task() As Integer
Dim val As Integer
For i = 1 To 999999999
val += 1
Next
Return val
End Function
'Async - Use existing Task - Async Method
Private Async Sub btn_async_use_task_Click(sender As Object, e As EventArgs) Handles btn_async_use_task.Click
Dim tsk As Task(Of Integer) = func_for_task_async()
Dim val As Integer = Await tsk
MsgBox(val)
End Sub
Private Async Function func_for_task_async() As Task(Of Integer)
Dim val As Integer
For i = 1 To 999999999
val += 1
Next
Return val
End Function
End Class

Answer 1

Don't ignore compiler warnings. In this case, the compiler will warn you that your async method does not use await, and therefore will run synchronously.
In your case, you can use Task.Run to execute func_for_task on a background thread, and await it from your click event handler.
For more info, see the async/await intro on my blog.