Question

Possible Duplicate:
Sort a Custom Class List<>

I have a Generic Collector List and some code adding CmsCategory in an unordered way to the Collector. CmsCategory has fields int CategoryId and string Title.

List<CmsCategory> categories = new List<CmsCategory>();
categories.Sort();

After the insertion is completed I need to to get all objects in the collector sorted by CategoryId (ascending).

I receive this error:

At least one object must implement IComparable.

My questions:

• What I’m doing wrong here using List<T>?

• Do you know more appropriate Generic Collector for this kind of operations?

Thanks for your time on this.

Answer 1

You can use the OrderBy() method to sort based on a property:

var sortedItems = categories.OrderBy(x => x.CategoryId);

If you need the items in a list, you can call .ToList():

var sortedList = sortedItems.ToList();

The cool thing about using OrderBy() is that you can also use ThenBy() with it to sort based on a second (or third, or fourth…) property as well:

var reallySortedItems = categories.OrderBy(x => x.CategoryId).ThenBy(x => x.OtherProp);