我怎样才能强制将throw用作语句而不是表达式(在lambda表达式中)? [英] How can I force a throw to be a statement and not an expression (in a lambda expression)?

问题描述

从C#7.0开始，throw关键字既可以用作表达式也可以用作语句，这很好. 不过，请考虑这些重载

Starting from C# 7.0 the throw keyword can be used both as an expression and as a statement, which is nice. Though, consider these overloads

public static void M(Action doIt) { /*use doIt*/ }
public static void M(Func<int> doIt) { /*use doIt*/ }

当这样调用时

M(() => throw new Exception());

甚至是这样(带有lambda语句)

or even like this (with a statement lambda)

M(() => { throw new Exception(); });

由编译器选择M(Func<>)重载，指示在这里将throw视为表达式. 我怎样才能优雅而明确地迫使编译器选择M(Action)重载?

the M(Func<>) overload is selected by the compiler indicating that the throw is here considered as an expression. How can I elegantly and intent-clear force the compiler to select the M(Action) overload?

做到这一点的一种方法是

One way to do it is this

M(() => { throw new Exception(); return; });

但是return语句的原因似乎并不明显，并且存在被下一个开发人员更改的风险，尤其是因为Resharper警告无法访问的代码.

but the reason for the return statement seems non-obvious, and runs the risk of being changed by the next developer especially since Resharper warns about the unreachable code.

(当然，我可以更改方法命名以避免重载，但这不是问题.:-)

(Of course I can change the method naming to avoid overloading, but that is not the question. :-)

推荐答案

您可以为Action添加类型转换，尽管它确实带有所有括号，但 LISP'y 有点:

You could add a cast to for Action, although it does get a bit LISP'y with all the parentheses:

M((Action)(() => throw new Exception()));

不理想，但是如果您想要最大的清晰度:

Not ideal, but if you want maximum clarity:

Action thrw = () => throw new Exception();
M(thrw);

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