Windows 7 Aero Theme Progress Bar Bug?

It has to do with the animation of the progress bar. If your progress bar is at 0% and you set it to 100% then it will not jump there, but animate the progress bar smoothly filling up. If this is too slow, you will be done before the progress bar finished animating. So even though you have already set it to 80, 90 and 100%, the animation still lags behind.

I never found a way to turn this off, however I have a workaround. The animation is only being done if you increment the progress bar. If you move it backwards, it will immediately jump to that position. So if I want the progress bar to be at x% (x != 100) then I move it to x+1 and then to x. If I want it at 100% I move it to 100, 99 and 100%. (Or whatever values you use, you get the idea.) This works fast enough to not to be visible, and you can leave this code in for previous Windows versions as well (though I don't).

I had the same problem. Fozi's tipp was helping me. Before setting a new value I have set the value + 1. To make this work also for 100% the maximum must be increased before. The following worked fine for me.

if (NewValue < progressBar.Maximum)
{
  progressBar.Value = NewValue + 1;
  progressBar.Value--;
}
else
{
  progressBar.Maximum++;
  progressBar.Value = progressBar.Maximum;
  progressBar.Value--;
  progressBar.Maximum--;
}

I think the original problem is related to timing and Win7's (or Aero's) animation mechanism for the progress bar.

This Sub is on the form that contains the progress bar (pBar).

It varies the bar's .Maximum and keeps .Value fixed at 10 for percent completes of 1 to 99. The bar's .Minimum is set to 0 at design time.

This sorted out the problem for me.

Public Sub UpdateStatusPC(ByVal pc As Integer)

    Try

        If pc < 0 Then
            pBar.Maximum = 100
            pBar.Value = 0
        ElseIf pc > 100 Then
            pBar.Maximum = 100
            pBar.Value = 100
        ElseIf pc = 0 Then
            pBar.Maximum = 10
            pBar.Value = 0
        Else
            pBar.Value = 10
            pBar.Maximum = 10 / CDbl(pc / 100.0)
        End If

        pBar.Update()

    Catch ex As Exception

        MsgBox("UpdateStatusPC: " & ex.Message)

    End Try

End Sub