如何在.NET中克隆字典？ [英] How do you clone a dictionary in .NET?

问题描述

我知道我们应该使用字典而不是哈希表。我找不到克隆字典的方法。即使将它强制转换为ICollection以获取SyncRoot，我也不知道。

I know that we should rather be using dictionaries as opposed to hashtables. I cannot find a way to clone the dictionary though. Even if casting it to ICollection which I do to get the SyncRoot, which I know is also frowned upon.

我现在正忙着更改它。我是在正确的假设下，无法以通用方式实现任何类型的克隆，这就是为什么字典不支持克隆的原因？

I am busy changing that now. Am I under the correct assumption that there is no way to implement any sort of cloning in a generic way which is why clone is not supported for dictionary?

推荐答案

使用带字典的构造函数。参见以下示例

Use the Constructor that takes a Dictionary. See this example

var dict = new Dictionary<string, string>();

dict.Add("SO", "StackOverflow");

var secondDict = new Dictionary<string, string>(dict);

dict = null;

Console.WriteLine(secondDict["SO"]);

而且只是为了好玩。您可以使用LINQ！

And just for fun.. You can use LINQ! Which is a bit more Generic approach.

var secondDict = (from x in dict
                  select x).ToDictionary(x => x.Key, x => x.Value);

编辑

这对引用类型应该很好用，我尝试了以下操作：

This should work well with Reference Types, I tried the following:

internal class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public User Parent { get; set; }
}

以及上面的修改代码

var dict = new Dictionary<string, User>();

dict.Add("First", new User 
    { Id = 1, Name = "Filip Ekberg", Parent = null });

dict.Add("Second", new User 
    { Id = 2, Name = "Test test", Parent = dict["First"] });

var secondDict = (from x in dict
                  select x).ToDictionary(x => x.Key, x => x.Value);

dict.Clear();

dict = null;

Console.WriteLine(secondDict["First"].Name);

哪个输出为 Filip Ekberg。

Which outputs "Filip Ekberg".

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