对象@object是什么意思

Question

I've been playing around with events and delegates and need to raise my event asynchronously, thus I've been using:

public event EventHandler OnHelloEvent;

public void Raise()
{
    IAsyncResult syncResult = OnHelloEvent.BeginInvoke(this, new EventArgs(), null, null)

In Intellisense, the last null is stated to be object @object . I haven't come across this before and can't seem to find any documentation for it.

What does this mean? Is it useful?

Answer 1

The @ sign can be thought of as "escape" character of sorts. Since object is a keyword in C#, you cannot use it as a variable name. However prefix it with an @ character and it no longer is a keyword, just a valid variable name!

Answer 2

@允许您使用保留关键字作为参数的名称。

Answer 3

That is the special character for escaping reserved words so that they can be used as identifiers.

See Section 2.4.2 of the specification .

Answer 4

Everyone answered "What does this mean?" but nobody answered "Is it useful?"

In most cases, the answer is No . You should not use this.

There are a few special exceptions. Off the top of my head:

1. Interoperability issues with someone else's code: Someone else's code requires you to have a variable with a name of a reserved word. Maybe their code was written in a language with different reserved words than C#.
2. Computer-generated code: It doesn't hurt to use an @ symbol. If you're paranoid about reserved word collisions, you might decide that all variables in your computer-generated code will use an @ symbol. Or maybe you are allowing a non-C# program to generate C# programs via a scripting language or whatever and you want to support variables named class .

Answer 5

The @ symbol is just a prefix which allows you to use a reserved identifier as a variable name.

So object @object , defines a variable of type object called object.