Public Class frmHoover
 
    Dim WithEvents btn As New Button With _
     {.Parent = Me, .Width = 300, .Height = 300}
    Dim WithEvents tim As New Timer With _
      {.Interval = 100, .Enabled = False}
 
    Dim MouseEnteredButton As Boolean 'Maus betritt oder verläßt den Button?
    Dim ImageKey As Integer = 0       'Schlüssel des angezeigten ( 
    ' Zwischen)bildes 
 
    Private Sub frmHoover_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
 
        Dim pc As New cPicCombine
        pc.Bitmap1 = New Bitmap(<Bilddatei bei Maus über Button>)
        pc.Bitmap2 = New Bitmap(<Bilddatei, angezeigt sonst>)
 
        'Bilderliste mit Kombi-Bildern erstellen
        Dim il As New ImageList
        il.ImageSize = New Size(250, 250)
        For i As Integer = 0 To 100 Step 10
            il.Images.Add(CStr(i), CType(pc.Combine(i), Image))
        Next i
        btn.ImageList = il
        btn.ImageKey = "0"
    End Sub
 
    Private Sub btn_MouseEnter(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles btn.MouseEnter
        tim.Enabled = True
        MouseEnteredButton = True
        ImageKey = 0
    End Sub
 
    Private Sub btn_MouseLeave(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles btn.MouseLeave
        tim.Enabled = True
        MouseEnteredButton = False
        ImageKey = 100
    End Sub
 
 
    Private Sub tim_Tick(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles tim.Tick
 
        If MouseEnteredButton Then
            ImageKey += 10 'Bildserie ansteigend
        Else
            ImageKey -= 10 'Bildserie fallen
        End If
 
        If ImageKey > 100 Or ImageKey < 0 Then
            tim.Enabled = False 'Nach Durchlaufen Timer anhalten
        Else
            btn.ImageKey = CStr(ImageKey) 'Bild aktualisieren
        End If
    End Sub
End Class