“.@checked”的含义和名称是什么?

What is ".@checked" meaning and called?

当我阅读 C# 源代码时,我看到一行

return new Form(ElementType.Checkbox, ((IHTMLInputElement)htmlElement).@checked);  

但我无法通过关键字 .@checked 找到它。
能否请您告诉我 .@checked 的名称及其含义?

更新答案
首先,感谢@Yeldar Kurmangaliyev、@Erik Funkenbusch 和@TcKs。
其次,很抱歉重复 post。因为我用“.@checked”搜索,什么也没看到。
最后,我明白了 @ 符号帮助定义了一个名称与 C# keyword 相同的变量,就像这样:

string @string = "This is a string";
string str = @string; // str = "This is a string"

checkedkeyword in C#,因此名称必须以 @ 为前缀,如文档所述:

Keywords are predefined, reserved identifiers that have special meanings to the compiler. They cannot be used as identifiers in your program unless they include @ as a prefix. For example, @if is a valid identifier but if is not because if is a keyword.

所以 ((IHTMLInputElement)htmlElement).@checked) 意味着访问 class 实例上的 checked 成员实现 IHTMLInputElement.