<DllImport("user32.dll")> _
    Private Shared Function SendMessage( _
       ByVal hWnd As IntPtr, _
       ByVal wMsg As Int32, _
       ByVal wParam As Int32, _
       ByRef lParam As Int32) _
       As Int32
    End Function
    Private Const LVM_FIRST = &H1000
    Private Const LVM_SETEXTENDEDLISTVIEWSTYLE = LVM_FIRST + 54
    Private Const LVS_EX_GRIDLINES = &H1
    Private Const LVS_EX_CHECKBOXES = &H4
    Private Const LVS_EX_FULLROWSELECT = &H20

SendMessage(lstInseln.Handle, LVM_SETEXTENDEDLISTVIEWSTYLE, LVS_EX_GRIDLINES, 1)