请帮我添加一下窗体登陆代码好吗？

private sub ok_click()

    If IsNull(Me.username) Then
        MsgBox "选择登录用户名!"
        Me.username.SetFocus
        Exit Sub
    End If
    If IsNull(Me.password) Then
        MsgBox "请输入密码!"
        Me.password.SetFocus
        Exit Sub
    End If
    If Not IsNull(DLookup("员工编号", "管理员", "用户名 ='" & Me.username & "'and 密码  =" & Me.password)) Then
         DoCmd.OpenForm "主页"
          DoCmd.Close acForm, Me.Name
    Else
        MsgBox "密码或用户名不正确!"
        Me.username = ""
        Me.password = ""
        Me.username.SetFocus
    End If

End Sub

 

Private Sub cancel_Click()
    DoCmd.Close
End Sub