Dim prevdate As Date, tt As New ToolTip
Private Sub MonthCalendar1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) _
Handles MonthCalendar1.MouseMove
Dim hit As MonthCalendar.HitTestInfo = MonthCalendar1.HitTest(e.Location)
If hit.Time <> prevdate Then
tt.SetToolTip(sender, hit.Time.ToString)
prevdate = hit.Time
End If
End Sub