c# - 如何使用 LINQ to XML 创建对象列表？

Question

我尝试使用 LINQ 读取一些入站 XML 以生成对象列表：

<SCResponse>
<link href="http://192.168.6.126:8001/affiliate/account/81/notifications?startRow=2&amp;limit=20" rel="next_page" title="Next"/>
<link href="http://192.168.6.126:8001/affiliate/account/81/notifications?startRow=1&amp;limit=20" rel="previous_page" title="Previous"/>
<RecordLimit>20</RecordLimit>
<Notifications>
    <Notification href="http://192.168.6.126:8001/affiliate/account/81/notifications/24">
        <NotificationDate>2013-03-15T16:41:37-05:00</NotificationDate>
        <NotificationDetails>Notification details 1</NotificationDetails>
        <Status>New</Status>
        <NotificationTitle>Test notification 1</NotificationTitle>
    </Notification>
</Notifications>
<RecordsReturned>1</RecordsReturned>
<StartingRecord>1</StartingRecord>
<TotalRecords>1</TotalRecords>

我创建了一个简单的 POCO 对象来表示“通知”：

public class Notification
{
    public System.DateTime notificationDate;

    public string notificationDetails;

    public string status;

    public string notificationTitle;

    public string href;
}

我想阅读传入的 XML 并创建一个对象列表。

List<Notification> notificationList; 

XElement x = XElement.Load(new StringReader(result));
if (x != null && x.Element("Notifications") != null)
{
    notificationList = x.Element("Notifications")
                .Elements("Notification")
                .Select(e => new Notification()
                .ToList();
}

我真的不清楚'e'部分以及如何初始化一个新的 Notification 对象。你能帮忙吗？

Answer 1

e只是您传递给lambda 表达式的参数名称，new Notification(). 你可以像这样使用它：

notificationList = x.Element("Notifications")
                    .Elements("Notification")
                    .Select(e => new Notification()
                                 {
                                     href = (string)e.Attribute("href")
                                     notificationDetails = (DateTime)e.Element("NotificationDate")
                                     notificationDate = (string)e.Element("NotificationDetails")
                                     status = (string)e.Element("Status")
                                     notificationTitle = (string)e.Element("NotificationTitle")
                                 }
                    .ToList();

或者，如果您更喜欢查询语法

notificationList =
    (from e in x.Element("Notifications").Elements("Notification")
     select new Notification()
            {
                href = (string)e.Attribute("href")
                notificationDetails = (DateTime)e.Element("NotificationDate")
                notificationDate = (string)e.Element("NotificationDetails")
                status = (string)e.Element("Status")
                notificationTitle = (string)e.Element("NotificationTitle")
            })
    .ToList();

Answer 2

使用对象初始化语法：

notificationList = x.Element("Notifications")
            .Elements("Notification")
            .Select(e => new Notification()
                            {
                                href = (string)e.Attribute("href"),
                                notificationDate = (DateTime)e.Element("NotificationDate"),
                                notificationDetails = (string)e.Element("NotificationDetails"),
                                status = (string)e.Element("Status"),
                                notificationTitle = (string)e.Element("NotificationTitle")
                            })
            .ToList();

请记住，您可以轻松地将对象如XElement和XAttribute转换为string、int、double等DateTime。完整列表可在此处找到：XElement 类型转换

Answer 3

notificationList = x.Element("Notifications")
    .Elements("Notification")
    .Select(e => new Notification()
        {
            notificationDate = DateTime.Parse(e.Element("NotificationDate").Value),
            notificationDetails = e.Element("NotificationDetails").Value,
            status = e.Element("Status").Value,
            notificationTitle = e.Element("NotificationTitle").Value,
            href = e.Attribute("href").Value
        }
    .ToList();