How do I cast a List<T> effectively?

Asked 2009-02-02T20:24:02.950

I have a

List<InputField>

but I need a

List<IDataField>

Is there a way to cast this in c#? Or use Linq to get same result?

I have two classes that implement the same interface:

interface IDataField { }
class InputField : IDataField { }
class PurchaseField : IDataField { }

This List comes from a Linq-to-Sql query:

List<InputField> list = (from i .... select i).ToList();

c# linq-to-sql

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2 Answers

You could also use List.ConvertAll.

Example:

List<IDataField> newList = oldList.ConvertAll(i => i as IDataField);

answered 2009-02-02T20:39:36.117

I don't know that a direct cast would have the desired effect. The rare few times I've done this, it's usually something like:

List<InputField> list = .....
List<IDataField> list2 = new (List<IDataField>((IDataField[])list.ToArray()));

answered 2009-02-02T20:25:59.670