"this"关键字作为属性 [英] The 'this' keyword as a property

问题描述

我非常了解C#，但这对我来说很奇怪.在某些旧程序中，我看到了以下代码:

I know C# well, but it is something strange for me. In some old program, I have seen this code:

public MyType this[string name]
{
    ......some code that finally return instance of MyType
}

它怎么称呼?这有什么用?

How is it called? What is the use of this?

推荐答案

它是索引器.声明之后，您可以这样:

It is indexer. After you declared it you can do like this:

class MyClass
{
    Dictionary<string, MyType> collection;
    public MyType this[string name]
    {
        get { return collection[name]; }
        set { collection[name] = value; }
    }
}

// Getting data from indexer.
MyClass myClass = ...
MyType myType = myClass["myKey"];

// Setting data with indexer.
MyType anotherMyType = ...
myClass["myAnotherKey"] = anotherMyType;

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