Linq问题:结合Where子句

Question

素不相识的!

我有一些看起来像这样的XML:

<Root>
    <SectionA>
        <Item id="111">
            <Options>
                <Option val="a" cat="zzz">
                    <Package value="apple" />
                    <Feature value="avacado" />
                </Option>
                <Option val="b" cat="yyy">
                    <Package value="banana" />
                    <Feature value="blueberry" />
                </Option>
            </Options>
        </Item>
        <Item id="222">
            <Options>
                <Option val="c" cat="xxx">
                    <Package value="carrot" />
                    <Feature value="cucumber" />
                </Option>
                <Option val="d" cat="www">
                    <Package value="dairy" />
                    <Feature value="durom" />
                </Option>
            </Options>
        </Item>
    </SectionA>
    <SectionB>
    .
    .
    .
    </SectionB>
</Root>

我想根据ITEM的ID属性为"111"得到PACKAGE和FEATURE值,OPTION的VAL属性为"a".

我不知道从哪里开始.我可以使用where选择ITEM节点,但我不确定如何将它与OPTION节点上的where子句相结合.有任何想法吗？

Answer 1

这适合我.

var doc = XDocument.Parse(s);

var items = from item in doc.Descendants("Item")
            where item.Attribute("id").Value == "111"
            from option in item.Descendants("Option")
            where option.Attribute("val").Value == "a"
            let package = option.Element("Package").Attribute("value")
            let feature = option.Element("Feature").Attribute("value")
            select new { Package = package.Value, Feature = feature.Value };

items.First().Feature; // = "avacado"
items.First().Package; // = "apple"

let如果需要,可以省略这些部分,它们只是为了使匿名类型更薄.

var items = from item in doc.Descendants("Item")
            where item.Attribute("id").Value == "111"
            from option in item.Descendants("Option")
            where option.Attribute("val").Value == "a"
            select new
            {
               Package = option.Element("Package").Attribute("value").Value,
               Feature = option.Element("Feature").Attribute("value").Value
            };

实际上,我有点像第二个.

而非查询Linq风格.

var items = doc.Descendants("Item")
               .Where(item => item.Attribute("id").Value == "111")
               .SelectMany(item => item.Descendants("Option"))
               .Where(option => option.Attribute("val").Value == "a")
               .Select(option => new
               {
                Package = option.Element("Package").Attribute("value").Value,
                Feature = option.Element("Feature").Attribute("value").Value
               });