blocks|key|694488|text|正如你所说的，它们是声明，声明实际上是完成某件事的声明。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|694489|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|$]]

As you said they're declarations, a statement is one which actually gets something done.

blocks|key|2313060|text|不，它们是声明。准确地说，类成员声明。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2313061|对于那些存在于方法之外的对象来说，这是完全合法的。否则，你就不能首先声明一个方法！|2313062|通过“语句”，这本书告诉你，你不能在方法之外进行方法调用。例如，以下代码是非法的：|2313063|public+void+DoSomething()
{
++++//+Do+something+here...
}

MessageBox.Show("This+statement+is+not+allowed+because+it+is+outside+a+method.");|code-block|syntax|javascript|2313064|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

No, they're declarations. Class member declarations, to be precise.

And it's perfectly legal for those to exist outside of a method. Otherwise, you couldn't declare a method in the first place!

By "statements", the book is telling you that you can't have things like method calls outside of a method. For example, the following code is illegal:

<pre><code>public void DoSomething()
{
 // Do something here...
}

MessageBox.Show("This statement is not allowed because it is outside a method.");
</code></pre>

blocks|key|2596975|text|在C#中没有“命令”这样的概念。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2596976|根据C#规范，静态/实例变量声明不属于C#中的语句-它是字段声明(这是类成员声明的一种类型)。有关示例，请参阅C#+4+spec的第10.5节。|offset|length|2596977|现在，声明局部变量的语句就是语句，正如规范中声明语句所定义的那样(第8.5节)。不过，它们只适用于当地人。有关C#+4中语句生成的完整列表，请参见第B.2.5节。|2596978|基本上，C#规范定义了所涉及的术语-因此，尽管您可能非正式地认为是“命令”之类的，但从正确性的角度来看，C#规范是权威的来源。(当然，除了它没有说出语言设计者的意思的地方。这非常罕见。)|2596979|entityMap|0|LINK|mutability|MUTABLE|url|http://download.microsoft.com/download/0/B/D/0BDA894F-2CCD-4C2C-B5A7-4EB1171962E5/CSharp%2520Language%2520Specification.doc^0|0|1J|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|6|7|W|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

There's no such concept as a "command" in C#.

And a static / instance variable declaration isn't categorized as a statement within C# - it's a field-declaration (which is a type of class-member-declaration) as per the C# spec. See section 10.5 of the <a href="http://download.microsoft.com/download/0/B/D/0BDA894F-2CCD-4C2C-B5A7-4EB1171962E5/CSharp%20Language%20Specification.doc" rel="nofollow">C# 4 spec</a> for example.

Now the statements which declare local variables are statements, as defined by declaration-statement in the spec (section 8.5). They're only used for locals though. See section B.2.5 for a complete list of statement productions within C# 4.

Basically, the C# spec defines the terminology involved - so while you might think informally of "commands" and the like, in a matter of correctness the C# spec is the source of authority. (Except for where it doesn't say what the language designers meant to say, of course. That's pretty rare.)

blocks|key|694678|text|类、命名空间、字段声明不是声明语句。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|694679|字段可以在带有表达式的方法外部初始化，但虽然表达式是语句，但有许多语句不是表达式(例如，if)。|offset|length|style|CODE|694680|这一切都归结于语言语法是如何定义术语的，而C#定义术语的方式是相当常见的(例如。非常类似于C和C%2B%2B)。|694681|entityMap^0|0|18|2|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

Classes, namespace, fields declarations are not declarations statements.

A field can be initialised outside a method with an expression but while an expression is a statement there are lots of statements that are not expressions (eg. <code>if</code>). 

It all comes down to how the language grammar defines the terms, and the way C# does it is pretty common (eg. very similar to C and C++).

blocks|key|4388292|text|如果你的意思是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4388293|class+Foo
{
++++int+count+=+0;
++++StringBuilder+buffer+=+new+StringBuilder();
}|code-block|syntax|javascript|4388294|count和buffer是使用初始化器表达式的声明。但是这段代码不包含任何语句。|4388295|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|$]]

If you mean:

<pre><code>class Foo
{
 int count = 0;
 StringBuilder buffer = new StringBuilder();
}
</code></pre>

The count and buffer are declarations using initializer expressions . But this code contains no statements.

blocks|key|694772|text|字段初始化器是用方法外部的代码编写的，但编译器将该代码放在构造函数内。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|694773|所以像这样的字段初始化器：|694774|class+Foo++{

++int+Bar+=+42;

}|code-block|syntax|javascript|694775|基本上是构造函数中的一个字段和一个初始化器：|694776|class+Foo++{

++int+Bar;

++Foo()+{
++++Bar+=+42;
++}

}|694777|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

A field initialiser is written with the code outside a method, but the compiler puts that code inside the constructor.

So a field initialiser like this:

<pre><code>class Foo {

 int Bar = 42;

}
</code></pre>

is basiclally a field and an initialiser in the constructor:

<pre><code>class Foo {

 int Bar;

 Foo() {
 Bar = 42;
 }

}
</code></pre>

Reading a book (VS 2010), it says that commands (statements) in .NET Csharp cannot exist outside of method.
I am wondering - field declaration etc, these are commands, are they not? And they exist at class level. Can somebody elaborate at this a bit?

Statements cannot exist outside of methods?

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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读一本书(VS 2010)，它说.NET Csharp中的命令(语句)不能存在于方法之外。我想知道-字段声明等等，这些都是命令，不是吗？它们存在于类级别。有人能详细解释一下吗？

问语句不能存在于方法之外吗？
EN

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问语句不能存在于方法之外吗？EN