Question

好的..我看过一些类似的讨论，所以我希望这是非常独特的。

我想初始化和修改List中的数据

该列表是User类的属性，它位于Dictionary

中

 internal class User
{
    public string ID { get; set; }

    public string Name { get; set; }

    public List<ContactNumber> AddressBook { get; set; }
}

internal class Program
{

    private static void Main(string[] args)
    {
        Dictionary<int, User> dic = new Dictionary<int, User>();
        dic.Add(1, new User { ID = "id1", Name = "name1" });
        dic.Add(2, new User { ID = "id2", Name = "name2" });
        dic.Add(3, new User { ID = "id3", Name = "name3", AddressBook = new List<ContactNumber>(){new ContactNumber(3432),new ContactNumber(3213)} });

        User user = dic.Where(z => z.Value.ID == "id3").FirstOrDefault().Value;

        Console.WriteLine(user.Name);
        DisplayList(user);
        //Console.WriteLine(user.AddressBook.ToString());

        //update the list
        addOrUpdate(dic,3,user);

        //var used = new User { ID = "id1", Name = "Harry" };
        //dic[1] = used;

         user = dic.Where(z => z.Value.ID == "id3").FirstOrDefault().Value;


        Console.WriteLine(user.Name);
        DisplayList(user);


    }

    private static void DisplayList(User user)
    {
        foreach (ContactNumber number in user.AddressBook)
        {
            Console.WriteLine(number.PhoneNumber);

        }
    }

    //determin list length

    public static void addOrUpdate(Dictionary<int, User> dic, int key, User user)
    {
        //sets a new user data and just replaces it in the dictionary
        //var used = new User { ID = "id1", Name = "Harry" };
        var used = new User{ ID = "id3", Name = "Henry" ,AddressBook = new List<ContactNumber>(){new ContactNumber(3111),new ContactNumber(4444)}};

        if (dic.TryGetValue(key, out user))
        {
            // yay, value exists!
            dic[key] = used;

        }
        else
        {
            // darn, lets add the value 
            dic.Add(key, used);
        }
    }



}

问题是我想获取用户信息，只需在列表中添加联系人号码即可。目前，它重写了整个列表，因为我在更新函数中创建了新版本的列表。

Answer 1

http://ideone.com/iI2Rxb 只是： dic[key].AddressBook.Add(new ContactNumber(666));

Answer 2

这似乎是一种解决方案。

            user.AddressBook.Add(new ContactNumber() { PhoneNumber = 121212});

来自MSDN Docs

Answer 3

不在帮助之下，只需添加到列表中（因为它被引用，它将更新你从字典中获得的任何内容）

user.AddressBook.Add（...新联系人号码）;

如何从Dictionary <int，object>向列表中添加值，列表在Object中

3 个答案: