XML 데이터 구조 예시

<?xml version="1.0"?>
<library>
  <book id="lib001">
    <author>김철수</author>
    <title>XML 마스터하기</title>
    <category>컴퓨터</category>
    <price>55.00</price>
    <published>2023-05-12</published>
  </book>
  <book id="lib002">
    <author>이영희</author>
    <title>.NET 정복</title>
    <category>프로그래밍</category>
    <price>48.50</price>
    <published>2022-11-30</published>
  </book>
</library>

XPath 처리 클래스 구조

public class XmlDataExplorer 
{
    private XPathDocument dataDoc;
    private XPathNavigator dataNavigator;
    
    public XmlDataExplorer(string filePath) 
    {
        dataDoc = new XPathDocument(filePath);
        dataNavigator = dataDoc.CreateNavigator();
    }
}

노드 순회 및 데이터 출력

public void TraverseNodes()
{
    dataNavigator.MoveToRoot();
    dataNavigator.MoveToFirstChild();
    
    while(dataNavigator.MoveToFirstChild()) 
    {
        if(dataNavigator.HasAttributes) 
        {
            Console.WriteLine($"도서 ID: {dataNavigator.GetAttribute("id", "")}");
        }
        
        XPathNavigator childNode = dataNavigator.Clone();
        childNode.MoveToFirstChild();
        do 
        {
            Console.WriteLine($"{childNode.Name}: {childNode.Value}");
        } 
        while(childNode.MoveToNext());
    }
}

조건별 노드 검색

public void FindByCriteria(string id)
{
    XPathExpression query = dataNavigator.Compile($"/library/book[@id='{id}']");
    XPathNodeIterator results = dataNavigator.Select(query);

    while(results.MoveNext()) 
    {
        XPathNavigator current = results.Current;
        Console.WriteLine($"도서 ID: {current.GetAttribute("id", "")}");
        Console.WriteLine($"제목: {current.SelectSingleNode("title").Value}");
    }
}

가격 기반 필터링

public void FilterByPrice(decimal minPrice)
{
    XPathExpression query = dataNavigator.Compile($"/library/book[price > {minPrice}]");
    XPathNodeIterator results = dataNavigator.Select(query);

    while(results.MoveNext()) 
    {
        XPathNavigator current = results.Current;
        Console.WriteLine($"제목: {current.SelectSingleNode("title").Value}");
        Console.WriteLine($"가격: {current.SelectSingleNode("price").Value}");
    }
}

집계 연산 수행

public void CalculatePriceMetrics()
{
    XPathExpression avgQuery = dataNavigator.Compile(
        "sum(/library/book/price) div count(/library/book/price)");
        
    object avgResult = dataNavigator.Evaluate(avgQuery);
    Console.WriteLine($"평균 가격: {avgResult}");
}