当返回单个实体时，Linq to XML查询有效，但需要为list< T> [英] Linq to XML query works when returning single entity but needs to be of list<T>

问题描述

给出此XML:

<foo>
   <xxx>Some XXX</xxx>
   <bar Attr1="true">Some Bar</bar>     
   <bar Attr2="true">Some Bar #2</bar>
   <bar>Some Bar #3</bar>
   <bar>Some Bar #4</bar>
</foo>

我有这个LINQ查询:

I have this LINQ query:

var foos = from query in xmlData.Descendants("foo")
       from bars in query.Elements("bar")
       select new FooClass
       {
    xxx = (string)query.Element("xxx"),
    barCollection = new BarClass
    {
        display = bars.Value,
        attr1Exists = (answers.Attribute("Attr1") != null ? true : false)
        attr2Exists = (answers.Attribute("Attr2") != null ? true : false)
        }
       };

如果将barCollection定义为BarClass，这将非常有用.

This works great if barCollection is defined as BarClass.

但是我需要它成为List< BarClass>.

However I need it to be List<BarClass>.

我尝试了其他方法，并且在bar是List< string>的情况下可以使用此方法:

I've tried other approaches, and got this to work if bar is a List<string>:

var foos = from query in xmlData.Descendants("foo") 
select new FooClass 
{ 
    xxx = (string)query.Element("xxx"), 
    bar = query.Elements("bar").Select(x => x.Value).ToList() 
};

但是我找不到混合两者的方法.

But I can't find a way to mix the two.

有人可以展示如何结合这两种解决方案，以便将BarCollection填充为用户定义的类型，即List< BarClass>吗?

Can someone show how to combine the two solutions so that BarCollection is populated as a user defined type, namely List<BarClass>?

更新:下面的最终工作代码，使用提供的解决方案

var foos = from query in xmlData.Descendants("foo") 
select new FooClass 
{ 
    xxx = (string)query.Element("xxx"), 
    bar = query.Elements("bar").Select(x => new BarClass
    {
        display = x.Value,
        attr1Exists = x("Attr1") != null ? true : false),
        attr2Exists = x("Attr2") != null ? true : false)
        }

    ).ToList() 
};

推荐答案

将.Select(x => x.Value)更改为.Select(x => new BarClass(...)).

这篇关于当返回单个实体时，Linq to XML查询有效，但需要为list&lt; T&gt;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！