c# - 使具体的返回类型通用

Question

考虑以下两种方法，它们本质上是相互复制和粘贴的版本

public static List<Book> GetSubSet(List<Book> incomingList)
        {
            List<Book> returnList = new List<Book>();
            Random r = new Random();
            Console.WriteLine("Enter size of random subset: ");
            int randomInt = 0;
            int size = Convert.ToInt32(Console.ReadLine());
            while (size > incomingList.Count)
            {
                Console.WriteLine("Size too large, enter smaller subset: ");
                size = Convert.ToInt32(Console.ReadLine());
            }
            while (returnList.Count < size)
            {
                randomInt = r.Next(incomingList.Count);
                if (!returnList.Contains(incomingList[randomInt]))
                {
                    returnList.Add(incomingList[randomInt]);
                }
            }
            return returnList;
        }

 public static List<Pet> GetSubSet(List<Pet> incomingList)
        {
            Random r = new Random();
            List<Pet> returnList = new List<Pet>();
            Console.WriteLine("Enter random subset size: ");
            int size = Convert.ToInt32(Console.ReadLine());
            while (size > incomingList.Count)
            {
                Console.WriteLine("Size too large.  Enter random subset size: ");
                size = Convert.ToInt32(Console.ReadLine());
            }
            while (returnList.Count < size)
            {
                int randomInt = r.Next(incomingList.Count);
                if (!returnList.Contains(incomingList[randomInt]))
                {
                    returnList.Add(incomingList[randomInt]);
                }
            }

            return returnList;
        }

显然这不是很面向对象，我希望有一个方法可以处理任何类型。我不想使用继承，因为书和狗之间没有逻辑联系，我也不想包含类型，因为包含也没有意义。所以我们留下了一个界面。有点像

 interface ISubset
    {

        IEnumerable<T> GetSubset();
    }

我见过，但我不知道如何让尖括号接受任何泛型。如何使 IEnumerable 类型泛化，以便我可以在任何类上实现 GetSubset 方法？

Answer 1

使其通用:

    public static List<T> GetSubSet<T>(List<T> incomingList)
    {
        Random r = new Random();
        List<T> returnList = new List<T>();
        Console.WriteLine("Enter random subset size: ");
        int size = Convert.ToInt32(Console.ReadLine());
        while (size > incomingList.Count)
        {
            Console.WriteLine("Size too large.  Enter random subset size: ");
            size = Convert.ToInt32(Console.ReadLine());
        }
        while (returnList.Count < size)
        {
            int randomInt = r.Next(incomingList.Count);
            if (!returnList.Contains(incomingList[randomInt]))
            {
                returnList.Add(incomingList[randomInt]);
            }
        }

        return returnList;
    }