using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication3
{
    interface IHoge<out T>
    {
        T Value { get; }
    }

    class HogeContainer
    {
        private IList<IHoge<ValueType>> values = new List<IHoge<ValueType>>();
        public IList<IHoge<ValueType>> Values
        {
            get
            {
                return this.values;
            }
            set
            {
                this.values = value;
            }
        }
    }

    class A<T> : IHoge<ValueType> where T : struct
    {
        public ValueType Value { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var cntnr = new HogeContainer();

            cntnr.Values.Add(new A<int>() { Value = 1 });
            cntnr.Values.Add(new A<char>() { Value = '1' });
            cntnr.Values.Add(new A<double>() { Value = 1.1d });

            foreach (var o in cntnr.Values)
            {
                Console.WriteLine(o.Value);
            }

            return;
        }
    }
}