Need help in trackbar

Use the ValueChanged event instead.
Set the TrackBar.Minimum to the smallest size of the Button, set the Maximum to the largest.
In the ValueChanged Event:

private void myTrackBar_ValueChanged(object sender, EventArgs e)
    {
    TrackBar tb = sender as TrackBar;
    if (tb != null)
        {
        myBubuttonToResize.Width = tb.Value;
        }
    }

[edit]Missed the VB bit! - OriginalGriff[/edit]

Private Sub myTrackBar_ValueChanged(sender As Object, e As EventArgs)
    Dim tb As TrackBar = TryCast(sender, TrackBar)
    If tb IsNot Nothing Then
        myBubuttonToResize.Width = tb.Value
    End If
End Sub