vb中keydown事件里方向组合键该怎么写

Dim W, D, S
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
If KeyCode = vbKeyW Then W = True
If KeyCode = vbKeyD Then D = True
If KeyCode = vbKeyS Then S = True
If W And D Then
Caption = "上+右=右斜上"
ElseIf S And D Then
Caption = "下+前=右斜下"
Else
Caption = "其它键"
End If
End Sub
Private Sub Form_KeyUp(KeyCode As Integer, Shift As Integer)
If KeyCode = vbKeyW Then W = False
If KeyCode = vbKeyD Then D = False
If KeyCode = vbKeyS Then S = False
End Sub