Linq to XML，选择给定节点的所有属性及其值

Question

我有一个 xml 映射文件，看起来像这样，

<colourMappings>
    <model name="modelX">
        <mapping colour="White" configCode="1"></mapping>
        <mapping colour="Aluminium" configCode="2"></mapping>
        <mapping colour="Black" configCode="3"></mapping>
        <mapping colour="Blue" configCode="4"></mapping>
        <mapping colour="White Pearl" configCode="5"></mapping>
        <mapping colour="Graphite" configCode="6"></mapping>
        <mapping colour="Gunmetal" configCode="7"></mapping>
        <mapping colour="Indigo" configCode="8"></mapping>
        <mapping colour="Red" configCode="9"></mapping>
    </model>
    <model name="modelY">
        <mapping colour="White" configCode="1" stConfigCode= "xx" dgConfigCode="hj"></mapping>
        <mapping colour="Aluminium" configCode="2" stConfigCode= "xy" dgConfigCode="gh"></mapping>
        <mapping colour="Black" configCode="3" stConfigCode= "xt" dgConfigCode="fg"></mapping>
        <mapping colour="Blue" configCode="4" stConfigCode= "sd" dgConfigCode="fg"></mapping>
        <mapping colour="White Pearl" configCode="5" stConfigCode= "df" dgConfigCode="df"></mapping>
        <mapping colour="Graphite" configCode="6" stConfigCode= "xc" dgConfigCode="df"></mapping>
        <mapping colour="Gunmetal" configCode="7"  stConfigCode= "cv" dgConfigCode="cv"></mapping>
        <mapping colour="Indigo" configCode="8"  stConfigCode= "zx" dgConfigCode="vb"></mapping>
        <mapping colour="Red" configCode="9"  stConfigCode= "fg" dgConfigCode="cv"></mapping>
    </model>
</colourMappings>

我希望能够在给定模型名称和颜色的情况下提取所有属性及其值，

例如

给定 ModelY 和 White，我想得到 configCode="1" stConfigCode= "xx" dgConfigCode="hj" 这可以是任何结构 - 数组、列表，无论

我一直在使用 Linq to XML 但无法获得正确的语法，

XDocument mappings = XDocument.Load(@"D:\colour_mappings.xml");
var q = from c in mappings.Descendants("model")
                    where (string)c.Attribute("name") == "modelY" && (string)c.Descendants("mapping").Attributes("colour").FirstOrDefault() == "White"
                    select c.Attributes();

有人知道如何做到这一点吗？

乐意使用任何方法，不一定非得是 Linq

Answer 1

更新

总结为一个方法：

public IEnumerable<XAttribute> GetAttributes(string modelName, string colour)
{
    XDocument mappings = XDocument.Load(@"D:\colour_mappings.xml");

    var q1 =
        from elm in mappings.Descendants("model")
        where (string)elm.Attribute("name") == "modelY"
        select elm;

    var q2 =
        from elm in q1.Descendants("mapping")
        where (string)elm.Attribute("colour") == "White"
        select elm.Attributes().Where(a => a.Name != "colour");


    foreach (IEnumerable<XAttribute> attributeList in q2)
    {
        foreach (XAttribute attribute in attributeList)
        {
            yield return attribute;
        }
    }
}

Answer 2

由于时间紧迫，我将使用两阶段流程，

但有兴趣了解这是否可以在一个查询中实现

var matchingModelXml = from c in mappings.Descendants("model")
                               where (string)c.Attribute("name") == "modelY"
                               select c;

var mappingAttributes = from b in matchingModelXml.Descendants("mapping")
                        where (string)b.Attribute("colour") == "White"
                        select b.Attributes();

Answer 3

只是因为我喜欢挑战，所以它在一个查询中：

XDocument test = XDocument.Parse("<colourMappings>    <model name=\"modelX\">        <mapping colour=\"White\" configCode=\"1\"></mapping>        <mapping colour=\"Aluminium\" configCode=\"2\"></mapping>        <mapping colour=\"Black\" configCode=\"3\"></mapping>        <mapping colour=\"Blue\" configCode=\"4\"></mapping>        <mapping colour=\"White Pearl\" configCode=\"5\"></mapping>        <mapping colour=\"Graphite\" configCode=\"6\"></mapping>        <mapping colour=\"Gunmetal\" configCode=\"7\"></mapping>        <mapping colour=\"Indigo\" configCode=\"8\"></mapping>        <mapping colour=\"Red\" configCode=\"9\"></mapping>    </model>    <model name=\"modelY\">        <mapping colour=\"White\" configCode=\"1\" stConfigCode= \"xx\" dgConfigCode=\"hj\"></mapping>        <mapping colour=\"Aluminium\" configCode=\"2\" stConfigCode= \"xy\" dgConfigCode=\"gh\"></mapping>        <mapping colour=\"Black\" configCode=\"3\" stConfigCode= \"xt\" dgConfigCode=\"fg\"></mapping>        <mapping colour=\"Blue\" configCode=\"4\" stConfigCode= \"sd\" dgConfigCode=\"fg\"></mapping>        <mapping colour=\"White Pearl\" configCode=\"5\" stConfigCode= \"df\" dgConfigCode=\"df\"></mapping>        <mapping colour=\"Graphite\" configCode=\"6\" stConfigCode= \"xc\" dgConfigCode=\"df\"></mapping>        <mapping colour=\"Gunmetal\" configCode=\"7\"  stConfigCode= \"cv\" dgConfigCode=\"cv\"></mapping>        <mapping colour=\"Indigo\" configCode=\"8\"  stConfigCode= \"zx\" dgConfigCode=\"vb\"></mapping>        <mapping colour=\"Red\" configCode=\"9\"  stConfigCode= \"fg\" dgConfigCode=\"cv\"></mapping>    </model></colourMappings>");

var maps = from model in test.Root.Elements("model")
           from attr in model.Attributes("name")
           from mapping in model.Elements("mapping")
           where attr.Value == "modelY" && mapping.Attribute("colour").Value == "White"
           select new
           {
                 configCode = mapping.Attribute("configCode").Value
               , stConfigCode = mapping.Attribute("stConfigCode").Value
               , dgConfigCode = mapping.Attribute("dgConfigCode").Value
           };

foreach (var map in maps)
{
    Console.Write("configCode: ");
    Console.WriteLine(map.configCode);
    Console.Write("stConfigCode: ");
    Console.WriteLine(map.stConfigCode);
    Console.Write("dgConfigCode: ");
    Console.WriteLine(map.dgConfigCode);
}

Answer 4

我知道这现在已经很古老了，但我认为在不进行不必要的处理的情况下解决这个问题的方法看起来像这样：

mappings.Root.Elements()
        .Where(cm => cm.Attribute("name").Value == "modelY")
        .SelectMany(cm => cm.Elements()
                            .Where(m => m.Attribute("colour").Value == "White")
                            .SelectMany(m => m.Attributes()));

在查询格式中，它将是：

from cm in doc.Root.Elements()
where cm.Attribute("name").Value == "modelY"
from m in cm.Elements()
where m.Attribute("colour").Value == "White"
from att in m.Attributes()
select att;