Using Lambda expressions to order a list by GMT date
I have a list that contains dates that are in GMT forma开发者_如何学编程t.
What is the most elegant way to ensure that the following Lambda expression orders on the date field as GMT?
ProductsList.OrderBy(Product => Product.Added).ToList();
The inbuilt LINQ operators use the expected sort operations (for LINQ-to-Objects, it does this using Comparer<T>.Default
. Your lambda expression is strongly typed; behind the scenes the compiler inferred some generics for you - it is actually:
var newList = Enumerable.OrderBy<Product,DateTime>(
ProductsList, Product => Product.Added).ToList();
It already knows it is a DateTime
, so the only time you'd need to do something extra here is if your dates contain a range of different timezones. Of course, within a timezone you should be fine, but you could (if you were paranoid) convert all to UTC - I don't think you need to do this in your case, but:
var newList = ProductsList.OrderBy(
Product => Product.Added.ToUniversalTime()).ToList();
Note that this actually creates a second list (it doesn't change the ordering of the original list); you can use the code from here to do an in-place sort using lambdas:
ProductsList.Sort(Product => Product.Added);
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