Question

一、导言

public SharpQuery Each(Action<int, HtmlNode> function)
{
    for (int i = 0; i < _context.Count; ++i)
        function(i, _context[i]);
    return this;
}

此处每一要素的用词都是起作用的。可否确定“这”指的是<代码>Action<int, HtmlNode>Function?

例如,

sharpQuery.Each((i, node) => /* `this` refers to an HtmlNode here */);

Answer 1

<>第号

是的,如果《行动》是在可动用且受封锁约束的范围内建立的——但透明:无。

Pass in all needed information or make sure it s captured/available in the Action itself. There are other hacks like thread-locals, etc. Best avoided.

Answer 2

由于职能略有变化,你可以取得预期的效果。

public SharpQuery Each(Action<MyObject, int, HtmlNode> function)
{
    for (int i = 0; i < _context.Count; ++i)
        function(this, i, _context[i]);
    return this;
}

接着,你可以照样写你的职责:

sharpQuery.Each((self, i, node) => /* do something with `self` which is "this" */);

Note: The anonymous function will only have access to public members however. If the anonymous function was defined within the class, it will have access to protected and private members as usual.

例如,

class MyObject
{
    public MyObject(int i)
    {
        this.Number = i;
    }

    public int Number { get; private set; }
    private int NumberPlus { get { return Number + 1; } }

    public void DoAction(Action<MyObject> action)
    {
        action(this);
    }

    public void PrintNumberPlus()
    {
        DoAction(self => Console.WriteLine(self.NumberPlus));  // has access to private `NumberPlus`
    }
}

MyObject obj = new MyObject(20);
obj.DoAction(self => Console.WriteLine(self.Number));     // ok
obj.PrintNumberPlus();                                    // ok
obj.DoAction(self => Console.WriteLine(self.NumberPlus)); // error

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