How can I sort a List<T> by a property of the objects in C#?

General Discussions
1

I have a class Order with properties like OrderId, OrderDate, Quantity, and Total. I also have a List<Order> filled with orders. I want to sort this list by a specific property, such as OrderDate or OrderId.

How can I accomplish this in C# using C# list sort methods?

2

Hey! I’ve done this tons of times :sweat_smile:. The simplest way is to use the Sort method with a lambda:

orders.Sort((x, y) => x.OrderDate.CompareTo(y.OrderDate));

This sorts the list in-place by OrderDate.

I usually use CompareTo for date, numeric, or string comparisons, it’s fast and reliable.

If you want descending order, just flip the parameters:

orders.Sort((x, y) => y.OrderDate.CompareTo(x.OrderDate));

3

Using LINQ’s OrderBy or OrderByDescending

If you prefer functional style, LINQ works beautifully:

var sortedOrders = orders.OrderBy(o => o.OrderDate).ToList();

OrderBy creates a new sorted list, leaving the original list untouched.

For descending order, just use OrderByDescending:

var sortedOrdersDesc = orders.OrderByDescending(o => o.Total).ToList();

I often use this when I want to keep the original list intact for later reference.

4

Sometimes I need to sort by more than one property, e.g., OrderDate and then Quantity. I usually do:

var sortedOrders = orders
    .OrderBy(o => o.OrderDate)
    .ThenBy(o => o.Quantity)
    .ToList();

ThenBy allows secondary sorting rules.

I’ve found this super useful when generating reports or displaying orders in a UI.