access登錄窗口校驗代碼一

Private Sub login_Click()
If IsNull(Me.username) Then
MsgBox "請輸入用戶名！", vbExclamation
ElseIf IsNull(Me.password) Then
MsgBox "請輸入密碼！", vbExclamation
ElseIf key1 = DLookup("password", "user", "用戶名 = '" & Me.username & "'") Then
DoCmd.OpenForm "登錄界面" '打開登錄界面
Else
MsgBox "密碼不正確！", vbExclamation
End If
End Sub