LINQ OrderBy with more than one field
I have a list that I need sorted by two fields. I've tried using OrderBy in LINQ but that only allows me to specify one field. I'm looking for the list to be sorted by the first field and then if there are any duplicates in the first field to sort by the second field.
For example I want the results to look like this (sorted by last name then first name).
I've seen that you can use the SQL like syntax to accomplish this but I am looking for a way to do it with the OrderBy method.
IList<Person> listOfPeople = /*The list is filled somehow.*/
IEnumerable<Person> sortedListOfPeople = listOfPeople.OrderBy(aPerson => aPerson.LastName, aPerson.FirstName); //This doesn't work.
你需要使用ThenBy ：
listOfPeople.OrderBy(person => person.LastName)
.ThenBy(person => person.FirstName)
If you want to use method syntax, use ThenBy() , as others suggested:
listOfPeople.OrderBy(person => person.LastName)
.ThenBy(person => person.FirstName)
In query syntax, the same can be accomplished pretty much the way you wanted: two sort keys separated by a comma:
from person in listOfPeople
orderby person.LastName, person.FirstName
select person
The above code will be actually compiled to code that uses OrderBy() and ThenBy() , as in the first example.
Also, if you'd like to have OrderBy() that takes two (or more) sort keys, you can certainly write that as an extension method on IEnumerable<T> that internally calls OrderBy() and ThenBy() .
您的后续字段应使用ThenBy（）方法进行排序
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