LINQ to XML-子类化XElement [英] LINQ to XML - subclassing XElement

问题描述

在构建文档时，我想对XElement进行子类化，以添加一些更强大的类型检查.不幸的是，我发现自己被限制在库的重要部分之外.

I would like to subclass XElement to add a bit of stronger type checking when I am constructing a document. Unfortunately I found to be locked out of the important part of the library.

// only illustrative

class TopLevelBlock:XElement {

class TopLevelBlock : XElement {

TopLevelBlock(XName name):base(name){} } class Parargaph:TopLevelBLock {

TopLevelBlock(XName name) : base(name) {} } class Parargaph : TopLevelBLock {

Paragraph():base(W.p){}

Paragraph() : base(W.p) {}

//由于内部限制，无法实现

// not possible due to internal restriction

//公共重写XNode CloneNode(){
    //   返回新的段落(this);
    //} } 类表:TopLevelBlock { } class StructuredDocumentTag:TopLevelBlock { }

    // public override XNode CloneNode() {
    //    return new Paragraph(this);
    // } } class Table : TopLevelBlock { } class StructuredDocumentTag : TopLevelBlock { }

para = Paragraph();

para = Paragraph();

parent.Add(para); //将保留为段落

parent.Add(para); // it will stay as Paragraph

parent.Add(para); //由于CloneNode类型的结果将更改为XElement

parent.Add(para); // as a result of CloneNode type will change to XElement

一切都很好，只要我正在构建文档并且不调用任何触发CloneNode的LINQ转换即可.当我点击CloneNode时，所有内容都将降级为XElement.

Everything is fine as long as I am constructing document and not calling any LINQ transformations triggering CloneNode. As soon as I hit CloneNode, everything gets downgraded to XElement.

CloneNode已被标记为虚拟，但不幸的是内部.将来是否有机会放宽此限制?

The CloneNode is marked already as virtual, but unfortunately internal. Is there any chance to relax this restriction in the future?

也许使用c#/.net的其他机制可以更好地完成我想做的事情.欢迎任何建议.

Perhaps there is a better way of accomplishing what I am trying to do using other mechanism of c#/.net. Any suggestions are welcome.

-pawel

在将XText子类化时，其他人报告了类似的困难，http://blogs.msdn.com/b/ericwhite/archive/2010/01/21/writing-entity-references-using-linq-to-xml.aspx

Other people reported similar difficulties when subclassing XText, http://blogs.msdn.com/b/ericwhite/archive/2010/01/21/writing-entity-references-using-linq-to-xml.aspx

推荐答案

您应该在这里使用封装而不是继承.

You should use encapsulation, rather than inheritance here.

 class TopLevelBlock
  {
    readonly XElement doc;

    TopLevelBlock(string name)
    {
      doc = new XElement((XName)name);
      doc.SetAttributeValue("someAttribute","");

    }

    public int someAttribute
    {
      get
      {
        return int.Parse(doc.Attribute("someAttribute").Value);
      }
      set
      {
        doc.SetAttributeValue("someAttribute", value.ToString());
      }
    }
  }

也许是XML序列化.

David

这篇关于LINQ to XML-子类化XElement的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！