Why does this generic cast fail?

Question

I have the following inheritance:

internal abstract class TeraRow{}

internal class xRow : TeraRow {} // xRow is a child of TeraRow

public IEnumerable

        

Answer 1

If you need the casted list to perform like the original reference (setting an item at an index also sets the item in the original collection, you can create a wrapper class that implements IList. (Unless I'm missing something), for a general purpose solution you'll need two due to generic constraint limitations:

public class UpCastList : IList
    where FromType : ToType

public class DownCastList
    where ToType : FromType

The other possibility is delegating the conversion:

public class CastList : IList
{
    public CastList(IList source, Func converter) { ... }
}

Edit: if you only need an IEnumerable, then you can use the Cast extension method as mentioned earlier.