blocks|key|4566929|text|在您的示例中，实际上不是。但是，第一种情况可以很容易地扩展为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4566930|Console.WriteLine("MyVariable+value+is+{0}+and+myothervar+is+{1}",+i,+j);|code-block|syntax|javascript|4566931|对于第二种方法，这可能是一个小麻烦。|4566932|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

in your example, practically not. However, the first case can easily be extended to do 

<pre><code>Console.WriteLine("MyVariable value is {0} and myothervar is {1}", i, j);
</code></pre>

which could be a little cumbersom with the second approach.

blocks|key|564334|text|在this+thread中查看答案。在简单的情况下，这并不重要，但如果您在大型循环或其他地方执行此操作，则需要考虑性能。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|564335|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/16432/c-string-output-format-or-concat^0|1|B|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Check out the answer in <a href="https://stackoverflow.com/questions/16432/c-string-output-format-or-concat">this thread</a>. In a simple case it doesn't really matter, but there are performance considerations if you are doing this in a large loop or something.

blocks|key|2667921|text|也许这会对将来的某个人有所帮助。现在有了第三种方法(插值)，它是所有方法中最干净的！它们都是用不同的方式写出相同的东西。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2667922|int+i+=+12;

//+Interpolation+Method-+Req.+C#+6+or+later+[Cleanest]
Console.WriteLine($"MyVariable+value+is+{i}");

//+Concatenation+Method+(from+VB+days)
Console.WriteLine("MyVariable+value+is+"+%2B+i);+

//+Format+Method+(from+C+days)
Console.WriteLine("MyVariable+value+is+{0}",+i);|code-block|syntax|javascript|2667923|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Maybe this will help someone in the future. There is now a 3rd method(Interpolation) and it is the cleanest of them all! They are all just different ways of writing the same thing.

<pre><code>int i = 12;

// Interpolation Method- Req. C# 6 or later [Cleanest]
Console.WriteLine($"MyVariable value is {i}");

// Concatenation Method (from VB days)
Console.WriteLine("MyVariable value is " + i); 

// Format Method (from C days)
Console.WriteLine("MyVariable value is {0}", i);
</code></pre>

blocks|key|4283399|text|我相信你在为初学者编写的书中看到了字符串连接，因为它很简单。在如此简单的示例中使用字符串格式之前，需要先解释它。字符串连接非常简单，在书中可能已经教过了(即使没有，它也足够简单，可以通过示例学习)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4283400|我可以看出，当C程序员第一次遇到这种格式语法时，他们可能会对它感到困惑。当试图将它扩展到两个变量时，他们可能会认为它需要这样编写：|4283401|int+numA+=+3;
int+numB+=+5;
Console.WriteLine("numA+is+{0}+and+numB+is+{0}",+numA,+numB);|code-block|syntax|javascript|4283402|我认为它将类似于C的printf，其中{0}等同于%25d|offset|length|style|CODE|4283403|printf("numA+is+%25d+and+numB+is+%25d",+numA,+numB);|4283404|当然，如果varA被打印两次，他们会感到惊讶。或者，当尝试Console.WriteLine字符串时，他们可能会因为不知道%25s的等价物而感到沮丧。另一方面，字符串连接的缺陷更少，初学者可以更容易地扩展。当然，它更混乱，但也更强大，这在一本介绍C#的书中可能会让人感到困惑，因为字符串格式化语法可能会变得相当复杂：|4283405|Console.WriteLine("numA+is+{0,17:$00.00####}",+numA);|4283406|上面的例子还说明了连接和字符串格式化之间的区别。它们是不同的，但对于像您创建的这样的简单用法，几乎没有什么不同。|4283407|entityMap^0|0|0|0|A|6|J|3|P|2|0|0|5|4|T|H|1P|2|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|11|8|@$K|12|L|13|M|N]|$K|14|L|15|M|N]|$K|16|L|17|M|N]]|9|@]|A|$]]|$1|O|3|P|5|F|7|18|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|19|8|@$K|1A|L|1B|M|N]|$K|1C|L|1D|M|N]|$K|1E|L|1F|M|N]]|9|@]|A|$]]|$1|S|3|T|5|F|7|1G|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|1H|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|X|$]]

I believe you see the string concatenation in books for beginner because it is simple. String formatting needs to be explained before it can be used in such simple example. String concatenation is much simple and may already have been taught at that point in the book (even if not, it is simple enough to learn by example).

I can see how C programmers might be confused by the format syntax when encountering it for the first time. When attempting to extend it to two variables they might think it needs to be written as so:

<pre><code>int numA = 3;
int numB = 5;
Console.WriteLine("numA is {0} and numB is {0}", numA, numB);
</code></pre>

Thinking it would be similar to C's <code>printf</code> where <code>{0}</code> is equivilant to <code>%d</code>:

<pre><code>printf("numA is %d and numB is %d", numA, numB);
</code></pre>

They would of course be surprised to have <code>varA</code> be printed twice. Or they may be frustrated of not knowing the equivalent of <code>%s</code> when trying to <code>Console.WriteLine</code> a string. String concatenation, on the other hand, has fewer pitfalls and can be more easily extended by beginners. Of course it is more cluttered but also more powerful, power that may be confusing in a book introducing someone to C# since string formatting syntax can grow quite complex:

<pre><code>Console.WriteLine("numA is {0,17:$00.00####}", numA);
</code></pre>

The above example also illustrates the difference between concatenation and string formatting. They are different, but for simple usages like the one you made, it makes little difference.

blocks|key|566887|text|您的具体案例不会，以了解更多信息|type|unstyled|depth|inlineStyleRanges|entityRanges|data|566888|http://msdn.microsoft.com/en-us/library/ms228362.aspx|offset|length|566889|问候|566890|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1H|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]]]]

Your specific case will not, for more information

<a href="http://msdn.microsoft.com/en-us/library/ms228362.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/ms228362.aspx</a>

Regards

Confusion in a really a basic question:
I have seen in many books, they use use Console.WriteLine as:

<pre><code>int i = 12;
Console.WriteLine("MyVariable value is {0}", i);
</code></pre>

Instead of

<pre><code>int i = 12;
Console.WriteLine("MyVariable value is" + i);
</code></pre>

Is there any difference between them?

Console.WriteLine different ways of writing

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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一个非常基本的问题中的困惑:我在很多书中看到，他们使用Console.WriteLine作为：int i = 12;Console.WriteLine("MyVariable value is {0}", i);而不是int i = 12;Console.WriteLine("MyVariable value is" + i);它们之间有什么不同吗？

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