Simple, non-blocking way to sleep?

Question

Hello

I googled for this and read some threads here, but I haven't found a simple way to have a VB.Net application sleep for a little while and still keep the application responsive:

Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Text.RegularExpressions
Imports System.Threading.Thread

[...]

''#How to keep screen frop freezing?
While True
  ListBox1.Items.Clear()

  ListBox1.Items.Add("blah")

  ''#Not much difference
  ListBox1.Refresh()

  ''#Wait 1mn
  Sleep(60000)
End While

Is there really no simple, non-blocking solution to have a VB.Net application wait for a few seconds?

Thank you.

Answer 1

Is this WinForms or WPF?

If it's WinForms you could just use a timer instead of a while loop. Then your app would still be responsive and raise events.

In WPF I think you would have to make your own timer based on the DispatchTimer class.

Answer 2

The Timer suggestion is really the best way to do it. But if DoEvents still works (I haven't done VB since 5.0), you can do this:

For i = 0 To 600
    DoEvents
    Sleep(100)
Next

This would do 600 sleeps of .1 second each, with a DoEvents between each to handle current events. The .1 second should be a good tradeoff between responsiveness (events get handled within .1 second) and CPU consumtion (do this too fast and your app will start consuming a significant amount of CPU time even while waiting).

Answer 3

(I'll answer to myself since comments don't accept code)

By default, the Timer will trigger after the time has elapsed. Is there a way to force it run right when the application start instead of waiting for the Timer to strike? I couldn't call the Timer1_Tick() event:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    ''#Check every minute
    Timer1.Interval = 60000
    Timer1.Enabled = True
    ''#Timer1_Tick()
    Timer1.Start()

End Sub

Answer 4

Public Sub ResponsiveSleep(ByRef iMilliSeconds As Integer)
    Dim i As Integer, iHalfSeconds As Integer = iMilliSeconds / 500
    For i = 1 To iHalfSeconds
        Threading.Thread.Sleep(500) : Application.DoEvents()
    Next i
End Sub

Call ResponsiveSleep to pause a particular piece of code whilst keeping the application fairly responsive. To make the application more responsive iHalfSeconds could be modified to tenths or hundredths of a second