将一个IDisposable的处置，如果使用块的回报？ [英] Will a IDisposable be disposed if the using block returns?

问题描述

例如

 使用（VAR东西= GetSomething（））
{
    something.DoSomething（）;
    如果（something.IsX（））返回true;
}
返回false;
 

解决方案

是的，绝对。该处置方法被调用但是在执行使用语句，除非这是一个突然的全过程结束。最常见的情况是：

• A 返回块内的
• 在抛出异常（而不是抓）块内
• 接触块的结尾自然

基本上是一个使用语句主要是语法糖为尝试 / 最后块 - 和最后具有相同的所有属性。

编辑：从的<一节8.13 href="http://download.microsoft.com/download/0/B/D/0BDA894F-2CCD-4C2C-B5A7-4EB1171962E5/CSharp%20Language%20Specification.doc"相对=nofollow> C＃4规格：

  

A 使用语句stranslated分为三个部分：获取，使用和处置。资源的使用是隐式的由尝试语句，其中包括最后条款。这最后第处置的资源。

在最后语句在规范的第8.10描述：

  

在最后块中的语句总是被执行时，在控制离开尝试语句。这是真实的，不管该控制传输正常执行的结果;作为执行破发的结果，继续， GOTO 或返回语句;或为传播例外出来的结果是尝试语句。

For example

using(var something = GetSomething())
{
    something.DoSomething();
    if(something.IsX()) return true;
}
return false;

解决方案

Yes, absolutely. The Dispose method is called however the using statement is executed, unless it was an abrupt whole-process termination. The most common cases are:

• A return within the block
• An exception being thrown (and not caught) within the block
• Reaching the end of the block naturally

Basically a using statement is mostly syntactic sugar for a try/finally block - and finally has all the same properties.

EDIT: From section 8.13 of the C# 4 specification:

A using statement is stranslated into three parts: acquisition, usage, and disposal. Usage of the resource is implicitly enclosed in a try statement that includes a finally clause. This finally clause disposes of the resource.

The finally statement is described in section 8.10 of the specification:

The statements of a finally block are always executed when control leaves a try statement. This is true whether the control transfer occurs as a result of normal execution; as a result of executing a break, continue, goto or return statement; or as a result of propagating an exception out of the try statement.

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