So I have a custom type Foo:

public class Foo
{
    public string Description {get;set;}
    public int Order {get;set;} //not unique - just some integer
    public DateTime Date {get;set;}
}

and a list containing this Foos (see what I did there?):

public class FooTops : List<Foo>
{
    public string Description {get; set;}
    public DateTime Date {get; set}

    public void AddCustom(Foo foo)
    {
        if (this.Count == 0)
        {
            this.Description = foo.Description;
            this.Date = foo.Date;
        }
        else
        {
            if (foo.Order == 1)
            {
                this.Date = foo.Date;
            }
        }
        this.Add(foo);
    }
}

I now want to convert this list to a SortedList, but that list cannot take my custom type Foo.

How do I sort my list by Foo.Order? Basically I want to have many FooTops containing Foos sorted by their Foo.Order.

I read about using delegates to sort lists but they always do that afterwards and not "on each item added". Could I also sort my list afterwards?

I just made the list a SortedList<int,Foo>. The TKey is the Foo.Order. Of course this key is not unique, so before the `this.Add(foo);´ line I just generate a unique key myself:

private in CheckForUniqueOrder(int p)
{
    if (this.ContainsKey(p))
    {
        p = p +1;
        p = CheckForUniqueOrder(p); //love recursion...
    }
    return p;
}

Use the SortedList and use Foo.Order as key for the list.