XML序列化-多种类型的集合

Question

I want to put inside Submenu two different tags: Item and Separator and then parse XML document with XmlSerializer. I can do it when Submenu contains only Item sequence.

Exemplary XML document:

<?xml version="1.0" encoding="utf-8" ?>
<Navigation xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:noNamespaceSchemaLocation="...">
  <Menu Name="Main">
    <Item Caption="File">
      <Submenu>
        <Item Caption="New" Command="." />
        <Item Caption="Open" Command="." />
        <Separator />
        <Item Caption="Exit" Command="." />
      </Submenu>
    </Item>
  </Menu>
</Navigation>

And (not) working C# code:

[Serializable]
[XmlRoot("Navigation", IsNullable = false)]
public class Navigation
{
    [XmlElement("Menu")]
    public List<Menu> MenuCollection { get; set; }
}

[Serializable]
[XmlRoot("Menu", IsNullable = false)]
public class Menu
{
    [XmlAttribute("Name")]
    public string Name { get; set; }

    [XmlElement("Item")]
    public List<Item> Items { get; set; }
}

[Serializable]
[XmlRoot("Item", IsNullable = false)]
public class Item
{

    [XmlAttribute("Caption")]
    public string Caption { get; set; }

    [XmlAttribute("Command")]
    public string Command { get; set; }

    [XmlElement("Submenu", IsNullable = true)]
    public Menu Submenu { get; set; }
}

Menu.Items should contains Items and Separators. How can I do it?

Answer 1

Although conceptually a menu item and a separator are two different things, it's easiest to think of them both as menu items. Add a new property to your Menu class:

    [XmlAttribute]
    public bool IsSeparator { get; set; }

This way, Menu.Items need only ever contain Items . Your XML will end up with elements such as

    <Item IsSeparator="true" />