主页 / coding / 问题 / 77067268
Accepted
Andrew Truckle
Asked: 2023-09-08 21:20:59 +0800 CST

如何按日期倒序对数据列表进行排序？

  • 772

XML 示例：

<AssignmentHistory>
    <PublicTalkInfo>
        <PublicTalkNumber>21</PublicTalkNumber>
        <PublicTalkSpeaker>Name3</PublicTalkSpeaker>
        <PublicTalkCongregation>Place3</PublicTalkCongregation>
    </PublicTalkInfo>
    <PublicTalkInfo>
        <MeetingDate>2023-10-15</MeetingDate>
        <PublicTalkNumber>21</PublicTalkNumber>
        <PublicTalkSpeaker>Name</PublicTalkSpeaker>
        <PublicTalkCongregation>Place</PublicTalkCongregation>
    </PublicTalkInfo>
    <PublicTalkInfo>
        <MeetingDate>2023-11-15</MeetingDate>
        <PublicTalkNumber>21</PublicTalkNumber>
        <PublicTalkSpeaker>Name2 </PublicTalkSpeaker>
        <PublicTalkCongregation>Place</PublicTalkCongregation>
    </PublicTalkInfo>
</AssignmentHistory>

为了简化我把它删掉了。

public string[] GetHistoryForTalkOutline(string historyDatabase, int talknumber)
{
    List<string> list = new List<string>();
    try
    {
        XDocument doc = XDocument.Load(historyDatabase);
        var ptInfo = doc
                        .Descendants("PublicTalkInfo")
                        .Where(p => p.Element("PublicTalkNumber").Value == talknumber.ToString()).ToList();
        SimpleLog.Log(ptInfo.Count().ToString());
           foreach (var pt in ptInfo)
           {
               var date = pt.Element("MeetingDate");
               var speaker = pt.Element("PublicTalkSpeaker");
               var cong = pt.Element("PublicTalkCongregation");

               if (date != null && speaker != null && cong != null)
               {
                   DateTime objectdate = DateTime.Parse(date.Value);
                   string histitem = objectdate.ToString("d") + ", ";
                   histitem += speaker.Value + " (";
                   histitem += cong.Value + ")";
                   list.Add(histitem);
               }

           }

        return list.ToArray();
    }
    catch (Exception ex)
    {
        SimpleLog.Log(ex);
        return null;
    }
}

我确信代码可以简化。但是，如何构建最终的字符串列表，其中内容按日期降序排列？请注意，某些条目中没有字段。

c#

3 个回答

  1. Best Answer

    您可以将它们保留为保留日期值的格式，而不是将所有值存储在字符串列表中。例如，使用元组：

    List<(DateTime Date, string Value)> list = new List<(DateTime, string)>();

    稍后当您添加到列表时，请执行以下操作：

    list.Add((objectdate, histitem));

    要按您需要的顺序返回值，请使用一些简单的 Linq：

    return list
    .OrderByDescending(x => x.Date)
    .Select(x => x.Value)
    .ToArray();
    • 1

  2. 也许可以尝试一些类似的事情

    using System.Xml.Linq;

....
        var doc = XDocument.Parse(xml);
        
        var emptyDate = DateTime.MinValue;
        var sortedElements = doc.Root.Elements("PublicTalkInfo")
            .OrderByDescending(e => e.Element("MeetingDate") != null 
                ? (DateTime)e.Element("MeetingDate") 
                : emptyDate)
            .ToList();

    如果您希望没有会议日期的元素显示在列表顶部，您可以替换DateTime.MinValue->DateTime.MaxValue

    • 0

  3. 也许，这样的事情应该有所帮助：：

    using System.Xml.Linq;
XElement root = XElement.Load("file.xml");
var orderedtabs = root.Elements("PublicTalkInfo")
                    .OrderBy(xtab => (DateTime?)xtab.Element("MeetingDate"))
                    .ToArray();
root.RemoveAll();
foreach(XElement tab in orderedtabs)
    root.Add(tab);
root.Save("file-sorted.xml");
    • 0

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