导致方法从 lambda 返回

发布于 2024-09-12 07:28:21 字数 614 浏览 1 评论 0原文

我有一个流畅的验证 API，当提供的布尔结果为 false 时，它会抛出异常。这很好用。

我想对此进行改进，不是抛出异常，而是提供一些在结果为 false 时执行的功能，然后强制调用方法返回。例如，所提供的功能可能会创建一个响应，对其进行适当的初始化并返回它。

这样做可能吗？（我怀疑不是）。

解决方法似乎是初始化一个输出参数（响应），然后从调用方法返回该参数。

期望：

Ensure.That(request.IsValid(), () => new Response { Errors = request.Errors }); //I want lambda to force containing method reeturn

已实施：

Response response;
            Ensure.That(request.IsValid(), r => new Response{Errors = request.Errors}, out response);
            if (response.IsNotNull()) return response;

原文

I have a fluent validation API that throws an exception when a supplied boolean result is false. This works fine.

I'd like to improve upon this by, instead of throwing an exception, providing some functionality to execute if the result is false, and then forcing the calling method to return. Example, the supplied functionality might new up a response, initialise it appropriately and return it.

Is doing this even possible? (I suspect not).

Work around seems to be something like initializing an out param (the response), and returning that from the calling method.

Desired:

Ensure.That(request.IsValid(), () => new Response { Errors = request.Errors }); //I want lambda to force containing method reeturn

As implemented:

Response response;
            Ensure.That(request.IsValid(), r => new Response{Errors = request.Errors}, out response);
            if (response.IsNotNull()) return response;

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我一向站在原地 2024-09-19 07:28:21

基本上，调用方法必须知道要执行此操作。如何发出信号取决于您 - 返回值、out 参数等 - 但您不能从委托本身强制执行它，除非出现异常（异常）当然，仍然可能被抓住）。

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说谎友 2024-09-19 07:28:21

在我所知道的任何语言中，都无法控制调用者的逻辑执行路径。即使抛出异常也不会影响调用者，因为调用者可以简单地捕获它。

像这样的事情是通过 C++ 中的宏完成的，但 C# 没有提供类似宏的功能。

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没有心的人 2024-09-19 07:28:21

正如 Skeet 所说，你必须告诉你的方法你希望它如何返回你的数据。一个示例（对您的特定应用程序一无所知）可能是这样的：

public void CheckValidationRules(ValidationRuleSet rules, object obj)
{
  //Your validation code here.
  while(!SomeValue) // currently throws, but we're, instead calling a new method
    FixThisProblem(ValidationError, obj, out SomeValue);
}

private void FixThisProblem(ValidationError error, object objInError, out bool someValue)
{
  //Your Code to fix the problem, then check that rule again
  if(!someValue) // recursively try to fix?  throw an exception?  whatever
  someValue = true;
}

然后您的错误方法可以优雅地处理此问题，然后继续其操作。请注意，我在 while 循环中调用了 FixThisProblem() 方法，以便您可以递归地修复是否存在多个均返回相同错误的问题。

As Skeet said, you have to tell your method how you want it return your data. One example (knowing nothing about your specific app) could be something like this:

public void CheckValidationRules(ValidationRuleSet rules, object obj)
{
  //Your validation code here.
  while(!SomeValue) // currently throws, but we're, instead calling a new method
    FixThisProblem(ValidationError, obj, out SomeValue);
}

private void FixThisProblem(ValidationError error, object objInError, out bool someValue)
{
  //Your Code to fix the problem, then check that rule again
  if(!someValue) // recursively try to fix?  throw an exception?  whatever
  someValue = true;
}

Then your faulted method can handle this gracefully, and then continue with its operation. Note that I have the call to the FixThisProblem() method in a while loop so that you can recursively fix if there could be multiple problems that all return the same error.

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