C# : Sort list on custom property

This question already has an answer here:

How to Sort a List<T> by a property in the object 19 answers

---

This might be inefficient, but you could add a DateTime property to your MyEvent class that converts StartDate to a DateTime and sort on that:

public class MyEvent
{
    public int EventId{get;set;}
    public MyDate StartDate{get;set;}
    public DateTime MyStartDate { get { return DateTime.Parse(StartDate.MMDDYYYYHHMMSS); } }
}

var sorted = myEvents.OrderByDescending(e => e.MyStartDate);

Alternatively, you could make the class immutable and do the conversion when instantiating it:

public class MyEvent
{
    public MyEvent(int eventId, MyDate startDate)
    {
        EventId = eventId;
        StartDate = startDate;
        MyStartDate = DateTime.Parse(StartDate.MMDDYYYYHHMMSS);
    }

    public int EventId{get; private set;}
    public MyDate StartDate{get; private set;}
    public DateTime MyStartDate { get; private set; }
}

---

You can write it with Linq OrderyBy() or OrderByDescending method according to your need this way:

var outputDate = myEvents.OrderByDescending(x=>
                          {
                           DateTime parsedDate;
                           return DateTime.TryParseExact(x.StartDate, "MM/dd/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out parsedDate) ? parsedDate : DateTime.MinValue;
                          });

or proper way would be to create a custom IComparer for it:

public class StringDateComparer : IComparer<string>
{

    public int Compare(string date1, string date2)
    {
        DateTime parsedDate1;
        DateTime.TryParseExact(date1, "MM/dd/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out parsedDate1);


        DateTime parsedDate2;
        DateTime.TryParseExact(date2, "MM/dd/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out parsedDate2);



        if (parsedDate1 < parsedDate2)
            return -1;
        if (parsedDate1 > parsedDate2)
            return 1;


        return 0;
    }
}

and now call OrderByDescending() overload which takes IComparer object as parameter:

var outputDate = myEvents.OrderByDescending(x=>x.StartDate,new StringDateComparer());

链接地址: http://www.djcxy.com/p/70938.html

上一篇: 在c＃中对类对象排序

下一篇: C＃：自定义属性的排序列表