在linq中返回多個具有相同名稱的xml子項

Question

我有以下XML並希望將所有“Answers”子項作為List返回

<quiz xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="quiz.xsd">
    <mchoice>
        <question>What is the capital city of Australia?</question>
        <answer>Sydney</answer>
        <answer correct="yes">Canberra</answer>
        <answer>Melbourne</answer>
        <answer>Gold Coast</answer>
    </mchoice>
    <mchoice>
        <question>Launceston is the second largest city in which Australian state?</question>
        <answer>Victoria</answer>
        <answer>New South Wales</answer>
        <answer correct="yes">Tasmania</answer>
        <answer>Western Australia</answer>
    </mchoice>
</quiz>



public class Question
{
    public string QuestionText { get; set; }
    public List<Answer> Answers { get; set; }

}
public class Answer
{
    public string Answer1 { get; set; }
    public string Answer2 { get; set; }
    public string Answer3 { get; set; }
    public string Answer4 { get; set; }
}

我嘗試了以下linq查詢，但我被困在Answer字段中

public IEnumerable<Question> GetAll()
    {
        var questions = from docs in _doc.Descendants("mchoice")
                        select new
                        {
                            QuestionText = docs.Element("question").Value,
                            Answers = docs.Descendants("answer").SelectMany(e=>e.Element("answer").Value)

                        };
        return questions;

    }

Answer 1

把你的班級換成

public class Question
{
    public string QuestionText { get; set; }
    public List<string> Answers { get; set; }

}

然后你的查詢將是

var questions = from docs in _doc.Descendants("mchoice")
                        select new Question
                        {
                            QuestionText = docs.Element("question").Value,
                            Answers = docs.Elements("answer").Select(a=>a.Value).ToList()

                        };

Answer 2

我不太確定你的實體結構是否正確。 您似乎有一個List類型的Answers屬性，每個答案實體再次有4個（總是4？）答案！

我想，改變它會更有意義。

public class Question
{
    public string QuestionText { get; set; }
    public List<Answer> Answers { get; set; }

    public Question()
    {
        if (Answers == null)
            Answers = new List<Answer>();
    }

}
public class Answer
{
    public string Answer1 { get; set; }
}

您可以編寫一個方法，通過讀取XML來返回問題列表（帶有答案）

public static IEnumerable<Question> GetAll(XElement elm)
{
    var allQA = new List<Question>();
    var mchoices = elm.Descendants("mchoice").ToList();
    foreach (var choice in mchoices)
    {
        var answers = choice.Descendants("answer").ToList();
        var qA = new Question { QuestionText = choice.Descendants("question").SingleOrDefault().Value };
        foreach (var answer in answers)
        {
            qA.Answers.Add(new Answer { Answer1 = answer.Value});
        }
        allQA.Add(qA);               
    }
    return allQA;
} 

無論我想要什么，我都可以這樣稱呼它

XElement elm = XElement.Load(Server.MapPath(@"../YourFolder/sample.xml"));
//You can alternatively load from string/stream etc..
if (elm != null) 
{
  var questionList=GetAll(elm);
}

Answer 3

嘗試改變這個：

Answers1 = docs.Descendants("answer").SelectMany(e=>e.Element("answer").Value)

對此：

Answers1 = docs.Descendants("answer").SelectMany(e=>e.Value)