blocks|key|183468|text|这被称为TryParse模式，并且已经被微软记录在案。The+official+Exceptions+and+Performance+MSDN+page+says|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|183469|183470|考虑对在常见情况下可能引发异常的成员使用TryParse模式，以避免与异常相关的性能问题。|blockquote|183471|183472|183473|因此，如果您的代码在常规用例下意味着它可能抛出异常(比如解析一个整数)，那么TryParse模式是有意义的。|183474|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/exceptions-and-performance^0|4|8|V|1E|0|0|0|0|0|0|12|8|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|F|3|-4|5|6|7|11|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|12|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|13|8|@]|D|@]|E|$]]|$1|K|3|-4|5|6|7|14|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|N|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|U]]]]

This is known as the TryParse pattern and has been documented by Microsoft. The <a href="https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/exceptions-and-performance" rel="noreferrer">official Exceptions and Performance MSDN page says</a>:

<blockquote>
 Consider the TryParse pattern for members that may throw exceptions in common scenarios to avoid performance problems related to exceptions.
</blockquote>

Thus if you have code for which a regular use case would mean that it might throw an exception (such as parsing an int), the TryParse pattern makes sense.

blocks|key|3014336|text|(更正)正如Erik建议的那样，有官方的指导方针。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3014337|当我看到TrySomething方法时，我假设它是|offset|length|style|CODE|3014338|我期望的值不会抛出存在的返回值，它是通过‘parameter|3014339|there’|unordered-list-item|3014340|+Something方法返回的，它允许我自己处理任何异常。(编辑，杰西·韦伯建议)|3014341|3014342|3014343|entityMap^0|0|4|C|0|0|0|1|9|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|W|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|X|8|@]|9|@]|A|$]]|$1|M|3|N|5|L|7|Y|8|@$D|Z|E|10|F|G]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|R|$]]

(Corrected) There is official guideline, as Erik suggested. 

When I see <code>TrySomething</code> method, I assume it 

<ul>
<li>doesn't throw</li>
<li>returns <code>bool</code></li>
<li>if I expect value, it is returned via 'out' parameter</li>
<li>there exists <code>Something</code> method, that allows me to handle any exception myself. (edit, suggested by Jesse Webb)</li>
</ul>

blocks|key|187850|text|我认为当你想继续的时候，你应该使用try。方法是否返回某个值并不重要。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|187851|情况1:如果返回正常，您可以通过某种方式继续操作。|187852|情况2:如果它没有返回:它仍然是正常的；您可以用其他方法继续。|187853|如果您希望该方法输出一些值，那么可以使用out参数。|187854|示例|187855|int+value
if+(dictionary.TryGetValue("key",+out+value))
{
++++//+Proceed+in+some+way
}
else
{
++++//+Proceed+in+some+other+way
}|code-block|syntax|javascript|187856|entityMap^0|H|3|0|0|0|K|3|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|12|8|@]|D|@]|E|$]]|$1|N|3|O|5|P|7|13|8|@]|D|@]|E|$Q|R]]|$1|S|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|T|$]]

I think you should use <code>try</code> when you want to proceed. It doesn't matter that a method returns some value or not.
Case 1: if it returns fine, you can proceed in some way.
Case 2: if it does not return: it is still fine; you can proceed in some other way.
And if you expect some value as output of that method then use the <code>out</code> parameter.
<h3>Example</h3>
<pre><code>int value
if (dictionary.TryGetValue(&quot;key&quot;, out value))
{
 // Proceed in some way
}
else
{
 // Proceed in some other way
}
</code></pre>

blocks|key|185055|text|当你想要表明方法调用可能产生无效结果时，你必须在方法名中使用"Try“。按照.NET标准，顺便说一下，它不是一个会引发异常的函数，而是一个返回一些值或值的函数，从程序的角度来看，就是VALID，NON_VALID。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|185056|最后，这一切都与您决定在您的组中使用的命名约定有关。|185057|entityMap^0|2J|5|2P|9|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

You have to use "Try" in method name, when you want to manifest the fact that the method invokation can produce not valid result. Following the .NET standard it's, by the way, not a function that raises an exception, but the function that returns some <code>VALID</code> or <code>NON_VALID</code>, from the program perspective, value.

At the end, this all about naming convention you decide to use in your group.

blocks|key|183476|text|如果出现以下情况，请确保在方法名中包含try：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|183477|你不会抛出任何异常，你的方法有以下签名：bool+TrySomething(input,+out+yourReturn)，，|183478|，|unordered-list-item|183479|183480|183481|183482|183483|所以基本上，如果我们使用try-methods，我们只能得到一个布尔结果。|183484|所以下面的代码不会抛出任何异常：|183485|string+input+=+"blabla";
int+number;
if+(int.TryParse(input,+out+number))
{
//+wooohooo+we+got+an+int!
}+else
{
//dooh!
}|code-block|syntax|javascript|183486|然而，这段代码可以(在本例中将)抛出异常：|183487|string+input+=+"blabla";
int+number;
try
{
+++++number+=+int.Parse(input);+//throws+an+exception
}
catch+(Exception)
{
+++++//dooh!
}|183488|使用Try方法是一种更安全、更具防御性的编码方式。此外，如果代码片段#2不是整数，则需要更多的性能才能执行。|183489|entityMap^0|J|3|0|K|14|0|0|0|0|0|0|C|3|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1B|8|@]|D|@]|E|$]]|$1|K|3|I|5|6|7|1C|8|@]|D|@]|E|$]]|$1|L|3|I|5|J|7|1D|8|@]|D|@]|E|$]]|$1|M|3|-4|5|J|7|1E|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1J|8|@]|D|@]|E|$]]|$1|S|3|T|5|U|7|1K|8|@]|D|@]|E|$V|W]]|$1|X|3|Y|5|6|7|1L|8|@]|D|@]|E|$]]|$1|Z|3|10|5|U|7|1M|8|@]|D|@]|E|$V|W]]|$1|11|3|12|5|6|7|1N|8|@]|D|@]|E|$]]|$1|13|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]]|14|$]]

Make sure to include <code>try</code> in your methodname if:

<ul>
<li>you don't throw any exception</li>
<li>your method has the following signature: <code>bool TrySomething(input, out yourReturn)</code></li>
</ul>

So basically if we use <code>try</code>-methods we only get a boolean result back.

So the following code will not throw any exceptions:

<pre><code>string input = "blabla";
int number;
if (int.TryParse(input, out number))
{
// wooohooo we got an int!
} else
{
//dooh!
}
</code></pre>

Whereas this code can (and in this case will) throw exceptions:

<pre><code>string input = "blabla";
int number;
try
{
 number = int.Parse(input); //throws an exception
}
catch (Exception)
{
 //dooh!
}
</code></pre>

Using Try methods is a safer and more defensive way to code.
Also the code snippet #2 takes more performance to execute if it's not an integer.

blocks|key|3014397|text|Bob叔叔在他的书“Clean+Code”中给出了下面的例子。每当我们期望抛出异常时，我们都可以在方法名中使用Try前缀：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3014398|public+void+sendShutDown()
{
++++try{
++++++++tryToShutDown();
++++}+catch+(DeviceShutDownError+e)+{
++++++++logger.log(e);++++++++++++
++++}
}|code-block|syntax|javascript|3014399|然后(改编)：|3014400|private+void+tryToShutDown()
{
++++//some+code+with+no+error+handling,+but
++++//something+might+go+wrong+here
}|3014401|因为这是sendShutDown方法的职责，所以tryToShutDown方法不会进行任何错误处理。|3014402|微软的TryParse模式违反了干净的代码指南，即我们应该避免输出参数。|3014403|如果我们不是在开发新版本的C#，我们就不必遵循微软的所有指导方针。有时候他们并不是最好的。|3014404|entityMap^0|1J|3|0|0|0|0|4|C|O|D|0|3|8|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|S|3|T|5|6|7|1A|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|V|$]]

Uncle Bob gives the example below in his book Clean Code. Whenever we expect an exception to be thrown we can use the <code>Try</code> prefix to a method name:

<pre><code>public void sendShutDown()
{
 try{
 tryToShutDown();
 } catch (DeviceShutDownError e) {
 logger.log(e); 
 }
}
</code></pre>

And then (adapted):

<pre><code>private void tryToShutDown()
{
 //some code with no error handling, but
 //something might go wrong here
}
</code></pre>

The <code>tryToShutDown</code> method does not make any error handling, because that's the responsibility of the <code>sendShutDown</code> method.

The <code>TryParse</code> pattern of Microsoft violates the clean code guideline that says that we should avoid output parameters.

If we're not developing a new version of C#, we don't have to stick to all Microsoft guidelines. Sometimes they're not the best.

We were discussing with our coworkers on what it means if the method name starts with "Try".

There were the following opinions:

<ul>
<li>Use "Try" when the method can return a null value.</li>
<li>Use "Try" when the method will not throw an exception.</li>
</ul>

What is the official definition? What does "Try" say in the method name? Is there some official guideline about this?

When is "Try" supposed to be used in C# method names?

我们正在和我们的同事讨论如果方法名以"Try“开头意味着什么。有以下几点意见：当方法可以返回空值时，使用"Try“。当方法不引发异常时，使用"Try”。官方定义是什么？方法名中的“尝试”是什么意思？有关于这方面的官方指南吗？

问什么时候应该在C#方法名中使用"Try“？
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