C# sort custom class list

Question

I have that class

public class MyItem
{
    public Order OrderItem { get; set; }
    public string Status { get; set; }
}

the Status property can have values Error, Pending, Success

I want to sort the List<MyItem>() object basing on the Status property.

I know that I can replace the type of the Status property from string to int and then instead of Error, Pending, Success values I can have 1,2,3 and then the sort operation is simple. But I'm wondering how to do it if we must do the sorting on basing on the string type property.

Possible order:

Error, Pending, Success or Success, Pending, Error

how to do it by using LINQ ?

You can write a custom IComparer<string> but, like @PLB says, why not use an enum? — Jodrell
– Jodrell, Commented Jun 6, 2013 at 10:28

James · Accepted Answer · 2013-06-06 10:28:01Z

5

I would use an enum instead which by default gives each status an integer value e.g.

public enum Status
{
    Success,
    Pending,
    Error
}

var sortedList = myList.OrderBy(x => x.Status);
// sort by Success, Pending and then Error
var sortedList = myList.OrderByDescending(x => x.Status);
// sort by Error, Pending, Success

You can convert your existing strings to enum pretty easily:

var status = (Status)Enum.Parse(typeof(Status), statusString);

answered Jun 6, 2013 at 10:28

James

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2 Comments

Tony Over a year ago

I've done that already but I'm wondering about the string case

James Over a year ago

@Tony if you had to compare string's you would need to write your own IComparer<T> class or make your MyItem class implement IComparable<T>. However, I would definitely push for switching to enum in this case, it's the right way to go.

harriyott · Accepted Answer · 2013-06-06 10:46:43Z

4

Its better to parse to an enum but, you could make a custom comparer,

var customComparer = Comparer<string>.Create((x, y) =>
    {
        ...
    });

You can than pass the the comparer into sort and order by functions, like this,

var sortedList = myList.OrderBy(x => x.Status, customComparer);

edited Jun 6, 2013 at 10:46

harriyott

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answered Jun 6, 2013 at 10:33

Jodrell

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Comments

Erik Schierboom · Accepted Answer · 2013-06-06 10:32:05Z

The easiest way is probably to implement the IComparable<T> interface. Implementing this interface on your MyItem class will ensure that when ordering a list of MyItem instances, the ordering as specified in the CompareTo method will be used. For your use case, this would result in code like this:

public class MyItem : IComparable<MyItem>
{
    public string OrderItem { get; set; }
    public string Status { get; set; }

    public int CompareTo(MyItem other)
    {
        if (other == null)
        {
            return 1;
        }

        if (other.Status == this.Status)
        {
            return 0;
        }

        var statusAsInt = this.Status == "Error" ? 0 : (this.Status == "Pending" ? 1 : 2);
        var otherStatusAsInt = other.Status == "Error" ? 0 : (other.Status == "Pending" ? 1 : 2);

        if (statusAsInt == otherStatusAsInt)
        {
            return 0;
        }

        return statusAsInt < otherStatusAsInt ? -1 : 1;
    }
}

internal class Program
{
    private static void Main(string[] args)
    {
        var myItems = new List<MyItem> { new MyItem { Status = "Pending" }, new MyItem { Status = "Error" }, new MyItem { Status = "Success " } };

        myItems.Sort();

        foreach (var myItem in myItems)
        {
            Console.WriteLine(myItem.Status);
        }    
    }
}

djf · Accepted Answer · 2013-06-06 10:32:38Z

2

You could define a dictionary which reflects the required ordering

Dictionary<string, int> ordering = new Dictionary<string, int> {
  { "Error", 1 },
  { "Pending", 2 },
  ...
}

var sortedList = myList.OrderBy(x => ordering[x.Status]);

answered Jun 6, 2013 at 10:32

djf

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Comments

harriyott · Accepted Answer · 2013-06-06 10:32:12Z

1

As the orders happen to be alphabetical, you can do a simple

var result = myList.OrderBy(item => item.Status);

or

var result = myList.OrderByDescending(item => item.Status);

However, if you rename "Success" as "Complete", then it'll break, in which case I'd recommend one of the suggested enum answers.

answered Jun 6, 2013 at 10:32

harriyott

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Comments

pierroz · Accepted Answer · 2013-06-08 19:06:45Z

1

I think it would be better to change the type of Status and replace the String by an enum. You can then choose the order you want by assigning values to the different members of your enum, or directly order this member as desired by your order method, and keep a readable property.

edited Jun 8, 2013 at 19:06

answered Jun 6, 2013 at 10:28

pierroz

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Comments

Luis Filipe · Accepted Answer · 2013-06-06 10:33:41Z

0

I would go for the Enum option but given that it's not your preferred option you might try the following:

You can implement IComparable<MyItem> in your class MyItem

Over there implement your logic of ordering according to the Status property. If two status are equal you can even then order by OrderItem, if that suits you.

If you need an example feel free to say so

answered Jun 6, 2013 at 10:33

Luis Filipe

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Comments

Martin Brown · Accepted Answer · 2013-06-06 10:45:39Z

You can pass .OrderBy() a method that weights the strings using a switch like this:

     List<MyItem> lst = new List<MyItem>();

     lst.Add(new MyItem() { Status = "Pending" });
     lst.Add(new MyItem() { Status = "Error" });
     lst.Add(new MyItem() { Status = "Invalid String" });
     lst.Add(new MyItem() { Status = "Success" });

     var ascList =
        lst.OrderBy((x) => { switch (x.Status) { case "Error": return 0; case "Pending": return 1; case "Success": return 3; default: return 4; } });

     var descList =
        lst.OrderByDescending((x) => { switch (x.Status) { case "Error": return 0; case "Pending": return 1; case "Success": return 3; default: return 4; } });

     Console.WriteLine("Asc\n===");
     foreach (MyItem mi in ascList)
     {
        Console.WriteLine(mi.Status);
     }

     Console.WriteLine("\nDesc\n====");
     foreach (MyItem mi in descList)
     {
        Console.WriteLine(mi.Status);
     }
  }

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