在 C#/.NET 中将参数标记为不可为空? [英] Mark parameters as NOT nullable in C#/.NET?

问题描述

是否有一个简单的属性或数据协定可以分配给函数参数，以防止在 C#/.NET 中传递 null?理想情况下，这也会在编译时检查以确保文字 null 没有在任何地方使用它，并在运行时抛出 ArgumentNullException.

Is there a simple attribute or data contract that I can assign to a function parameter that prevents null from being passed in C#/.NET? Ideally this would also check at compile time to make sure the literal null isn't being used anywhere for it and at run-time throw ArgumentNullException.

目前我写的东西像......

Currently I write something like ...

if (null == arg)
  throw new ArgumentNullException("arg");

...对于我希望不是 null 的每个参数.

... for every argument that I expect to not be null.

同样，是否存在与 Nullable<> 相反的情况，从而导致以下失败:

On the same note, is there an opposite to Nullable<> whereby the following would fail:

NonNullable<string> s = null; // throw some kind of exception

推荐答案

遗憾的是，编译时没有可用的东西.

There's nothing available at compile-time, unfortunately.

我有点hacky 解决方案，我最近发布在我的博客上，它使用了新的结构和转换.

I have a bit of a hacky solution which I posted on my blog recently, which uses a new struct and conversions.

在带有代码契约的 .NET 4.0 中，生活会好很多.拥有实际的语言语法并支持非可空性仍然会很好，但代码契约将有很大帮助.

In .NET 4.0 with the Code Contracts stuff, life will be a lot nicer. It would still be quite nice to have actual language syntax and support around non-nullability, but the code contracts will help a lot.

我在 MiscUtil 中还有一个名为 ThrowIfNull 的扩展方法，这使得它更简单一些.

I also have an extension method in MiscUtil called ThrowIfNull which makes it a bit simpler.

最后一点 - 有什么理由使用if (null == arg)"而不是if (arg == null)"?我发现后者更容易阅读，前者在 C 中解决的问题不适用于 C#.

One final point - any reason for using "if (null == arg)" instead of "if (arg == null)"? I find the latter easier to read, and the problem the former solves in C doesn't apply to C#.

这篇关于在 C#/.NET 中将参数标记为不可为空?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！