使用Linq to XML创建深层对象图，重构？

Question

我正在使用LINQ to XML编写一个简单的XML文件解析器。

我希望为XML中的每个元素提供一个TreeNode对象（即一个简单的Tree结构）。我希望每个元素都是强类型的。

与之前使用的简单循环方法（使用System.XML）相比，它看起来很丑陋和冗余。有没有办法去除这里的裁员？

        XElement ops = XElement.Load(@"c:\temp\exp.xml");
        Tree<Element> domain = new Tree<Element>();
        domain.Root = new TreeNode<Element>();
        var cells =
                    from cell in ops.Elements("cell")
                    select new
                    {
                        TreeNodeObj = new TreeNode<Element>
                            (new Cell((string)cell.Attribute("name"), (string)cell.Attribute("name"), null)),
                        XElem = cell
                    };
        foreach (var cell in cells)
        {
            domain.Root.AddChild(cell.TreeNodeObj);
            var agents =
                    from agent in cell.XElem.Elements("agent")
                    select new
                    {
                        TreeNodeObj = new TreeNode<Element>
                            (new Agent((string)agent.Attribute("name"), (string)agent.Attribute("name"), null)),
                        XElem = agent
                    };
            foreach (var agent in agents)
            {
                cell.TreeNodeObj.AddChild(agent.TreeNodeObj);
                var nas =
                    from na in agent.XElem.Elements("node-agent")
                    select new
                    {
                        TreeNodeObj = new TreeNode<Element>
                            (new NodeAgent((string)na.Attribute("name"), (string)na.Attribute("name"), null)),
                        XElem = agent
                    };
                foreach (var na in nas)
                {
                    agent.TreeNodeObj.AddChild(na.TreeNodeObj);
                }
            }
        }

Answer 1

如果没有样本数据和实际类型，很难完全回答这个问题，但我会像下面那样重构它。

从最初的例子中，我假设我们不想搞乱实体的构造函数（Agent etc），并且我们想要保留单独的<！> quot; TreeNode<T> <！ > QUOT;模型，将我们的实体放在树中（而不是更改实体以将事物建模为关联集合）。我还假设我们可以使用IEnumerable<...>获得比实体更多的自由，所以我引入了一个接受<=>的构造函数，因为这允许使用LINQ子查询：

XElement ops = XElement.Load(@"c:\temp\exp.xml");
Tree<Element> domain = new Tree<Element>(
    from cell in ops.Elements("cell")
    select new TreeNode<Element>(
        new Cell(
            (string)cell.Attribute("name"),
            (string)cell.Attribute("name"), null
        ),
        from agent in cell.Elements("agent")
        select new TreeNode<Element>(
            new Agent(
                (string)agent.Attribute("name"),
                (string)agent.Attribute("name"), null
            ),
            from na in agent.Elements("node-agent")
            select new TreeNode<Element>(
                new NodeAgent(
                    (string)na.Attribute("name"),
                    (string)na.Attribute("name"), null
                )
            )
        )
    )
);

使用以下框架代码：

using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
class Tree<T>
{
    public TreeNode<T> Root { get; set; }
    public Tree() { }
    public Tree(IEnumerable<TreeNode<T>> children)
    {
        Root = new TreeNode<T>(children);
    }
}
class TreeNode<T>
{
    private List<TreeNode<T>> children;
    public IList<TreeNode<T>> Children
    {
        get
        {
            if (children == null) children = new List<TreeNode<T>>();
            return children;
        }
    }
    private readonly T value;
    public TreeNode() { }
    public TreeNode(T value) { this.value = value; }
    public TreeNode(T value, IEnumerable<TreeNode<T>> children)
            : this(children)
    {
        this.value = value;
    }
    public TreeNode(IEnumerable<TreeNode<T>> children)
    {
        children = new List<TreeNode<T>>(children);
    }
}
class Element { }
class Cell : Element {
    public Cell(string x, string y, string z) { }
}
class Agent : Element {
    public Agent(string x, string y, string z) { }
}
class NodeAgent : Element {
    public NodeAgent(string x, string y, string z) { }
}
static class Program
{
    static void Main()
    {
        XElement ops = XElement.Load(@"c:\temp\exp.xml");
        Tree<Element> domain = new Tree<Element>(
            from cell in ops.Elements("cell")
            select new TreeNode<Element>(
                new Cell(
                    (string)cell.Attribute("name"),
                    (string)cell.Attribute("name"), null
                ),
                from agent in cell.Elements("agent")
                select new TreeNode<Element>(
                    new Agent(
                        (string)agent.Attribute("name"),
                        (string)agent.Attribute("name"), null
                    ),
                    from na in agent.Elements("node-agent")
                    select new TreeNode<Element>(
                        new NodeAgent(
                            (string)na.Attribute("name"),
                            (string)na.Attribute("name"), null
                        )
                    )
                )
            )
        );
    }
}

Answer 2

如果没有您的类和源代码xml，很难为您提供您所需的确切代码，但这就是我喜欢构建XML解析的方式：

XDocument d = XDocument.Parse(@"<a id=""7""><b><c name=""foo""/><c name=""bar""/></b><b/><b2/></a>");
var ae = d.Root;

var a = new A
    {
        Id = (int)ae.Attribute("id"),
        Children = new List<B>(ae.Elements("b").Select(be => new B
        {
            Children = new List<C>(be.Elements("c").Select(ce => new C
            {
                Name = (string)ce.Attribute("name")
            }))
        }))
    };

给出xml：

<a>
  <b>
    <c name="foo"/>
    <c name="bar"/>
  </b>
  <b/>
  <b2/>
</a>

和班级：

class A
{
    public int Id { get; set; }
    public List<B> Children { get; set; }
}
class B
{
    public List<C> Children { get; set; }
}
class C
{
    public string Name { get; set; }
}