在 C# 中设置对成员字段的引用 [英] Setting a ref to a member field in C#

问题描述

我想为成员字段分配一个引用.但我显然不太了解 C# 的这一部分，因为我失败了 :-) 所以，这是我的代码:

I'd like to assign a reference to a member field. But I obviously do not understand this part of C# very well, because I failed :-) So, here's my code:

public class End {
    public string parameter;

    public End(ref string parameter) {
        this.parameter = parameter;
        this.Init();
        Console.WriteLine("Inside: {0}", parameter);
    }

    public void Init() {
        this.parameter = "success";
    }
}

class MainClass {
    public static void Main(string[] args) {
            string s = "failed";
        End e = new End(ref s);
        Console.WriteLine("After: {0}", s);
    }
}

输出为:

Inside: failed
After: failed

如何在控制台上获得成功"?

How do I get "success" on the console?

提前致谢，迪杰特拉

推荐答案

这里确实有两个问题.

一个，正如其他海报所说，你不能严格做你想做的事情(就像你可以用 C 和类似的东西).但是 - 行为和意图在 C# 中仍然很容易使用 - 你只需要按照 C# 的方式来做.

One, as the other posters have said, you can't strictly do what you're looking to do (as you may be able to with C and the like). However - the behavior and intent are still readily workable in C# - you just have to do it the C# way.

另一个问题是您尝试使用字符串的不幸尝试 - 正如其他海报中提到的那样 - 不可变 - 并且根据定义被复制.

The other issue is your unfortunate attempt to try and use strings - which are, as one of the other posters mentioned - immutable - and by definition get copied around.

所以，话虽如此，您的代码可以很容易地转换成这样，我认为这确实可以满足您的需求:

So, having said that, your code can easily be converted to this, which I think does do what you want:

public class End
{
    public StringBuilder parameter;

    public End(StringBuilder parameter)
    {
        this.parameter = parameter;
        this.Init();
        Console.WriteLine("Inside: {0}", parameter);
    }

    public void Init()
    {
        this.parameter.Clear();
        this.parameter.Append("success");
    }
}

class MainClass
{
    public static void Main(string[] args)
    {
        StringBuilder s = new StringBuilder("failed");
        End e = new End(s);
        Console.WriteLine("After: {0}", s);
    }
}

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