How to type constrain generics scenario

Question

I am trying to make a custom Collection<X, Y...> : ICollection<X>, IList<Y> of sorts. It inherits from ICollection<T> , and IList<T> because I decided to go with the generic versions as they are more modern. Here are the constraints I need:

• items of type T (value types or reference types) can be added to the collection.
• Items of type IEnumerable<T> or IEnumerable<IEnumerable<T>> so forth and so on infinitely down the line can also be added :)

How can you make a Generic class with these constraints, ie what would the where clause be? Is this even possible? Would this be an appropriate place to use the non-generic ICollection , IList and no generics?

Answer 1

As described on MSDN type constrain is possible and you can accept one or multiple constraints.

Also check WHERE usage

Hope it helps.

Answer 2

Is this what you want?

public interface IBlock<T> 
    where T : IBlock<T>
{
}

public class Block<T> : Collection<T>, IBlock<Block<T>>
{        
}


class Program
{
    static void Main(string[] args)
    {
        var list_1=new Block<int[]>();
        list_1.Add(new int[] { 1, 2, 3} );
        list_1.Add(new int[] { 4, 5} );
        var list_2=new Block<int[]>();
        list_2.Add(new int[] { -1, 4} );
        list_2.Add(new int[] { 2, 6, 8} );
        var list_list =new Block<Block<int[]>>();
        list_list.Add(list_1);
        list_list.Add(list_2);

        int x=list_list[1][0][1];
        // x=4
    }
}