blocks|key|647686|text|没有“最佳实践”。它是你感到舒适的东西，也是在你的情况下最有效的东西。只要你坚持这一点，你发布的任何解决方案都没有问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|647687|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

There is no "best practice". It is what you are comfortable with and what works best in your situation. As long as you are consistent with this, there is no problem with any of the solutions you've posted.

blocks|key|647725|text|我认为答案取决于函数正在做什么的语义，以及两个值之间的关系。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|647726|例如，TryParse方法接受一个out参数来接受解析的值，并返回一个bool来指示解析是否成功。这两个值实际上并不属于一起，因此，从语义上讲，使用out参数更有意义，代码的意图也更易于阅读。|offset|length|style|CODE|647727|但是，如果您的函数在屏幕上返回某个对象的X/Y坐标，则这两个值在语义上属于同一个值，最好使用struct。|647728|我个人避免对外部代码可见的任何东西使用tuple，因为检索成员的语法很笨拙。|647729|entityMap^0|0|3|8|H|3|Z|4|22|3|0|1A|6|0|J|5|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@$D|P|E|Q|F|G]|$D|R|E|S|F|G]|$D|T|E|U|F|G]|$D|V|E|W|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|10|8|@$D|11|E|12|F|G]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|M|$]]

I think the answer depends on the semantics of what the function is doing, and the relationship between the two values.

For example, the <code>TryParse</code> methods take a <code>out</code> parameter to accept the parsed value, and return a <code>bool</code> to indicate whether or not the parse succeeded. The two values don't really belong together, so, semantically, it makes more sense, and the intent of the code is easier to read, to use the <code>out</code> parameter.

If, however, your function returns X/Y coordinates of some object on the screen, then the two values semantically belong together and it would be better to use a <code>struct</code>.

I'd personally avoid using a <code>tuple</code> for anything that will be visible to external code becuase of the awkward syntax for retrieving the members.

blocks|key|865028|text|我将使用Out参数的方法，因为在第二种方法中，您需要创建和对象的Tuple类，然后向其添加值，我认为与返回out参数的值相比，这是一个开销很大的操作。但是，如果您想在Tuple+Class中返回多个值(实际上，这不能仅通过返回一个out参数来实现)，那么我将采用第二种方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|865029|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I will go with the approach of using Out parameter because in second approach you would require to create and object of Tuple class and then add value to it, which I think is an costly operation compared to returning the value in out parameter. Though if you want to return multiple values in Tuple Class (which infact can not be accomplished by just returning one out parameter) then I will go for second approach.

blocks|key|647873|text|您没有提到另一个选项，即拥有一个自定义类而不是结构。如果数据具有可以由函数操作的相关语义，或者实例大小足够大(根据经验，>+16字节)，则可以首选自定义类。不推荐在公共API中使用"out“，因为它与指针相关联，并且需要了解引用类型的工作原理。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|647874|https://msdn.microsoft.com/en-us/library/ms182131.aspx|offset|length|647875|元组在内部使用很好，但在公共API中使用起来很笨拙。因此，我的投票是在公共API的结构和类之间。|647876|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1I|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@$D|Q|E|R|1|S]]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|C]]]]

You did not mention one more option, which is having a custom class instead of struct. If the data has semantics associated to it which can be operated upon by functions, or the instance size is big enough (> 16 bytes as a rule of thumb), a custom class may be preferred.
Use of "out" is not recommended in public API because of its association to pointers and requiring understanding of how reference types work.

<a href="https://msdn.microsoft.com/en-us/library/ms182131.aspx" rel="nofollow">https://msdn.microsoft.com/en-us/library/ms182131.aspx</a>

Tuple is good for internal use, but it usage is awkward in public API.
So, my vote is between struct and class for public API.

blocks|key|647949|text|除了前面的答案之外，与System.Tuple不同，C#+7引入了值类型元组，它是一种引用类型，并且还提供了改进的语义。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|647950|您仍然可以将它们保留为未命名，并使用.Item*语法：|647951|(string,+string,+int)+getPerson()
{
++++return+("John",+"Doe",+42);
}

var+person+=+getPerson();
person.Item1;+//John
person.Item2;+//Doe
person.Item3;+++//42|code-block|syntax|javascript|647952|但是这个新特性真正强大的地方是拥有命名元组的能力。所以我们可以像这样重写上面的代码：|647953|(string+FirstName,+string+LastName,+int+Age)+getPerson()
{
++++return+("John",+"Doe",+42);
}

var+person+=+getPerson();
person.FirstName;+//John
person.LastName;+//Doe
person.Age;+++//42|647954|还支持解构：|647955|(string+firstName,+string+lastName,+int+age)+=+getPerson()|647956|entityMap^0|B|C|0|I|6|0|0|0|0|0|0|1M|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|15|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|V|$]]

Adding to the previous answers, C# 7 brings value type tuples, unlike <code>System.Tuple</code> that is a reference type and also offer improved semantics.

You can still leave them unnamed and use the <code>.Item*</code> syntax:

<pre><code>(string, string, int) getPerson()
{
 return ("John", "Doe", 42);
}

var person = getPerson();
person.Item1; //John
person.Item2; //Doe
person.Item3; //42
</code></pre>

But what is really powerful about this new feature is the ability to have named tuples. So we could rewrite the above like this:

<pre><code>(string FirstName, string LastName, int Age) getPerson()
{
 return ("John", "Doe", 42);
}

var person = getPerson();
person.FirstName; //John
person.LastName; //Doe
person.Age; //42
</code></pre>

Destructuring is also supported:

<code>(string firstName, string lastName, int age) = getPerson()</code>

Consider a function which returns two values. We can write:

<pre><code>// Using out:
string MyFunction(string input, out int count)

// Using Tuple class:
Tuple&lt;string, int&gt; MyFunction(string input)

// Using struct:
MyStruct MyFunction(string input)
</code></pre>

Which one is best practice and why?

Returning two values, Tuple vs 'out' vs 'struct'

考虑一个返回两个值的函数。我们可以这样写：// Using out:string MyFunction(string input, out int count)// Using Tuple class:Tuple<string, int> MyFunction(string input)// Using struct:...

问返回两个值，元组vs 'out‘vs 'struct’
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问返回两个值，元组vs 'out‘vs 'struct’EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问返回两个值，元组vs 'out‘vs 'struct’
EN