How Do I Sort IList<Class>?

Use OrderBy

Example

public class MyObject() 
{
    public int number { get; set; }
    public string marker { get; set; }
}

IList<MyObject> myobj = new List<MyObject>();
var orderedList = myobj.OrderBy(x => x.marker).ToList();

For a case insensitive you should use a IComparer

public class CaseInsensitiveComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        return string.Compare(x, y, StringComparison.OrdinalIgnoreCase);
    }
}

IList<MyObject> myobj = new List<MyObject>();
var orderedList = myobj.OrderBy(x => x.marker, new CaseInsensitiveComparer()).ToList();

I would go against using OrderBy with a list because it's a LINQ extension method, therefore:

• It wraps the list in an enumerable, then enumerates it and fills a new temporary list, then sorts this new list.
• It wraps the sorted list inside another enumerable.
• Then when you call ToList(), it iterates on it and fills another new list with the items.

In essence: it creates and fills 2 new lists and 2 enumerables in addition to the actual sorting. In comparison, List.Sort() sorts in place and create nothing so it's way more efficient.

My recommendation would be:

• If you know the underlying type, use List.Sort() or Array.Sort(array)
• If you don't know the underlying type, copy the List to a temporary array and sort it using Array.Sort(array) and return it.