How To Cast Ilist To ArrayList?

Question

Can I Cast IList into ArrayList?

if yes what should I do?

IList alls = RetrieveCourseStudents(cf);
ArrayList a = (ArrayList)alls;

Is that correct?

is has error:

Unable to cast object of type

Answer 1

As suggested in the comments, you should consider using generic collections instead

List<Student> students = RetrieveCourseStudents(cf).Cast<Student>().ToList() 

Answer 2

You'd only be able to cast alls to an ArrayList if it already is an ArrayList, i.e. if the object returned by RetrieveCourseStudents is an ArrayList.

If it isn't then you need to create a new object, luckly ArrayList has a constructor that can do this: new ArrayList(RetrieveCourseStudents(cf))

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It's worth noting that you should be using generics (such as List<T>) instead of ArrayList now, so unless you need to interact with some old code that can't be updated, i'd stay away from it.