为什么try语句（和catch子句）需要一个块？ [英] Why does the try statement (and catch clause) require a block?
问题描述
允许以下内容：
if（a == b）
SomeFunction（）;
else
OtherFunction（）;
以下不是：
尝试
DoSomething （）;
catch（例外e）
ProcessError（e）;
我检查了C＃语法并确认了，与所有其他
复合语句不同，它需要一个块 - 即：需要开口{和
关闭}。
我只是想要能够写下面的内容（避免太多
缩进）：
尝试
使用（FileStream file = new FileStream（" someFile.txt"，
FileMode.OpenOrCreate））
使用（SomeResource rsrc = new SomeResource（））
{
//在这里做东西
}
catch（例外e）
{
//在这里处理错误
}
re **** @ gmail.com 写道：
允许以下内容：
if（a == b）
SomeFunction（）;
else
OtherFunction（）;
以下不是：
尝试
DoSomething（）;
catch（例外e）
ProcessError（e）;
我最好的猜测（这只是一个猜测）是试用块不是免费的b / b
语言设计师希望它们脱颖而出。
-
..NET 2.0 for Delphi程序员
www.midnightbeach.com/.net
您需要了解的内容。
Jon Shemitz写道：
re **** @ gmail.com 写道：
>允许以下内容：
if（a == b）
SomeFunction（）;
OtherFunction（）;
以下不是：
尝试
DoSomething（）;
catch（例外e）
ProcessError（e）;
我最好的猜测（这只是一个猜测）是试用块不是免费的，而且语言设计师希望它们是站出来。
此外，try块和catch块都必须构成
唯一范围 - 内部声明的变量在外部不可见（也不是如果允许单一陈述，他们将是b $ b。出于这个原因，它需要使用大括号使其成为一个正式的块。
-cd
恕我直言，我相信这是风格和历史的结合。风格是主观的，我不会采取一种方式或者另一种方式来确定它是否是正确的。但是，C＃的一个特性是它是C和C ++系列语言的演变。由于C ++ try块具有
花括号，C＃使C ++程序员的迁移路径更容易。
你会发现C＃语法在很多方面类似于C ++。
那就是说，我认为有一个技术原因要求C＃设计为这样的b $ b因为VB.NET尝试阻止唐没有开头/结尾，这是一个没有它的语法示例。
Joe
-
http://www.csharp-station.com
" re **** @ gmail.com"写道：
允许以下内容：
if（a == b）
SomeFunction（）;
else
OtherFunction（）;
以下不是：
尝试
DoSomething（）;
catch（例外e）
ProcessError（e）;
我检查了C＃语法并且它确认了，与所有其他
复合语句不同，它需要一个块 - 即：开头{和
结束需要。
我只想写下面的内容（以避免太多
缩进）：
尝试
使用（FileStream file = new FileStream（" someFile.txt"，
FileMode.OpenOrCreate））
using（SomeResource rsrc =新的SomeResource（））
{
//在这里做东西
}
catch（例外e）
{
//这里处理错误
}
While the following is allowed:
if (a == b)
SomeFunction();
else
OtherFunction();
The following is not:
try
DoSomething();
catch (Exception e)
ProcessError(e);
I checked the C# grammar and it confirms that, unlike all other
compound statements, it requires a block - ie: the opening { and
closing } are required.
I just want to be able to write the following (to avoid too many
indents):
try
using (FileStream file = new FileStream("someFile.txt",
FileMode.OpenOrCreate))
using (SomeResource rsrc = new SomeResource())
{
// do stuff here
}
catch (Exception e)
{
// handle error here
}
re****@gmail.com wrote:
While the following is allowed:
if (a == b)
SomeFunction();
else
OtherFunction();
The following is not:
try
DoSomething();
catch (Exception e)
ProcessError(e);My best guess (and it IS just a guess) is that try blocks are not
free, and the language designers wanted them to stand out.
--
..NET 2.0 for Delphi Programmers
www.midnightbeach.com/.net
What you need to know.
Jon Shemitz wrote:re****@gmail.com wrote:
>While the following is allowed:
if (a == b)
SomeFunction();
else
OtherFunction();
The following is not:
try
DoSomething();
catch (Exception e)
ProcessError(e);
My best guess (and it IS just a guess) is that try blocks are not
free, and the language designers wanted them to stand out.In addition, both the try block and the catch block by necessity constitute
unique scopes - variables declared inside are not visible outside (nor would
they be if a single statement were allowed). For that reason, it makes
sense to require the braces to make it a formal block.
-cd
IMHO, I believe this is a combination of style and history. Style is
subjective and I don''t take a side one way or the other as to whether it is
correct or not. However, one of the features of C# is that it is an
evolution of the C and C++ family of languages. Since the C++ try block has
curly braces, C# makes the migration path easier for the C++ programmer.
You''ll find that C# syntax is similar in many ways to C++.
That said, I don''t think there is a technical reason requiring that C# be
designed that way because VB.NET try blocks don''t have begin/end, which is an
example of syntax that works without it.
Joe
--
http://www.csharp-station.com
"re****@gmail.com" wrote:
While the following is allowed:
if (a == b)
SomeFunction();
else
OtherFunction();
The following is not:
try
DoSomething();
catch (Exception e)
ProcessError(e);
I checked the C# grammar and it confirms that, unlike all other
compound statements, it requires a block - ie: the opening { and
closing } are required.
I just want to be able to write the following (to avoid too many
indents):
try
using (FileStream file = new FileStream("someFile.txt",
FileMode.OpenOrCreate))
using (SomeResource rsrc = new SomeResource())
{
// do stuff here
}
catch (Exception e)
{
// handle error here
}
这篇关于为什么try语句（和catch子句）需要一个块？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
