Question

我需要一些帮助，将带有子节点的XML转换为csv文件。

这是我的XML：

<Main>
  <root>
    <Name>Sample name1</Name>
    <StreetAddress>Sample Address1</StreetAddress>
    <Service>
      <Type>Outlet</Type>
      <PhoneNumber></PhoneNumber>
      <Openweekday>Closed</Openweekday>
    </Service>
    <Service>
      <Type>Mall</Type>
      <PhoneNumber></PhoneNumber>
      <Openweekday>Closed</Openweekday>
      </Service>
  </root>
  <root>
    <Name>Sample name2</Name>
    <StreetAddress>Sample Address2</StreetAddress>
    <Service>
      <Type>Shop</Type>
      <PhoneNumber></PhoneNumber>
      <Openweekday>Closed</Openweekday>
    </Service>
</Main>

预期的CSV结果：

Name,StreetAddress,Type,PhoneNumber,OpenweekDay,Type,PhoneNumber,OpenweekDay
Sample name1,Sample Address1,Outlet,,Closed,Mall,,Closed
Sample name2,Sample Address2,Shop,,Closed

尝试从MSDN获得此代码。但它会抛出一个空例外 -

XElement custOrd = XElement.Load("xxx.xml");
    string csv =
        (from el in custOrd.Element("Main").Elements("root")
         select
             String.Format("{0},{1},{2},{3},{4},{5},{6},{7}",
                 (string)el.Attribute("Name"),
                 (string)el.Element("StreetAddress"),
                 (string)el.Element("Service").Element("Type"),
                 (string)el.Element("Service").Element("PhoneNumber"),
                 (string)el.Element("Service").Element("Openweekday"),
                 (string)el.Element("Service").Element("Type"),
                 (string)el.Element("Service").Element("PhoneNumber"),
                 (string)el.Element("Service").Element("Openweekday"),
                 Environment.NewLine
             )
        )
        .Aggregate(
            new StringBuilder(),
            (sb, s) => sb.Append(s),
            sb => sb.ToString()
        );
    Console.WriteLine(csv);

让我知道如何管理linq中的空值。

Answer 1

实际问题是custOrd它自己已经引用了<Main>，因此Element("Main")上的custOrd调用将返回null，并调用Elements("root") on null肯定会触发null引用异常。

要解决该问题，您可以将custOrd更改为XDocument类型：

XDocument custOrd = XDocument.Load("xxx.xml");

...或只是删除.Element("Main")来电：

XElement custOrd = XElement.Load("xxx.xml");
string csv =
        (from el in custOrd.Elements("root")
        ......
        ......

将null强制转换为字符串是安全的，但如果有<root>没有子元素<service>，则代码将再次抛出空引用异常。

Answer 2

正如其他人提到的那样，在加载或解析xml时，main已被引用，所以你的起点应该是root。这将为您提供您正在寻找的结构。

        XElement dataSet1Tree = XElement.Parse(xml);
        var dataSet1List = dataSet1Tree.Elements().Select(
        root => new
        {
            Name = (string)root.Element("Name"),
            StreetAddress = (string)root.Element("StreetAddress"),
            Service = root.Elements("Service")
                .Select(service => new
                {
                    Type = (string)service.Element("Type"),
                    PhoneNumber = (string)service.Element("PhoneNumber"),
                    OpenWeekDay = (string)service.Element("Openweekday")
                })

        }).SelectMany(root => root.Service, (root, service) => new
        {
            Name = root.Name, 
            StreetAddress = root.StreetAddress , 
            Type = service.Type, 
            PhoneNumber = service.PhoneNumber,
            OpenWeekDay = service.OpenWeekDay
        }).Aggregate("",(sb,s)=> sb +=string.Format("{0},{1},{2},{3},{4}",
                                                    s.Name,
                                                    s.StreetAddress,
                                                    s.Type,
                                                    s.PhoneNumber, 
                                                    s.OpenWeekDay)+"\r\n");

Console.WriteLine(dataSet1List);

使用linq将子节点转换为csv格式的XML

2 个答案: