在C#8.0中调用方法之前，感叹号是什么意思? [英] What does exclamation mark mean before invoking a method in C# 8.0?

问题描述

我发现了一个看似用C#8.0版编写的代码.在代码中，在调用方法之前有一个感叹号.这部分代码是什么意思，最重要的是，它的用途是什么?

I have found a code written in C# seemingly version 8.0. In the code, there is an exclamation mark before invoking a method. What does this part of the code mean, and above all, what are its uses?

var foo = Entity!.DoSomething();

推荐答案

这将是空宽容运算符.
它告诉编译器这不是null，请相信我"，因此它不会针对可能的null引用发出警告.

This would be the null forgiving operator.
It tells the compiler "this isn't null, trust me", so it does not issue a warning for a possible null reference.

在这种特殊情况下，它告诉编译器 Entity 不为null.

In this particular case it tells the compiler that Entity isn't null.

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