当处置，为什么？

本文介绍了当处置，为什么？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我问一个问题有关此方法

//保存对象到磁盘公共静态无效SerializeObject< T>（这件T toSerialize，字符串文件名） {的XmlSerializer XmlSerializer的=新的XmlSerializer（toSerialize.GetType（））; 的TextWriter的TextWriter =新的StreamWriter（文件名）; xmlSerializer.Serialize（的TextWriter，toSerialize）; textWriter.Close（）; }

在我这还有一个额外的言论响应：

请确保您始终一次性处置等资源流和文本的读者和作家。这似乎并不在你的SerializeObject方法的情况。

所以，我可以告诉大家，这会显得超级跛脚有人谁已编码C＃为一年或两年，可是为什么我必须处理掉呢？

时看到 testWriter 具有Dispose方法，但不应垃圾收集采取照顾？我从德尔福为C＃。在Delphi中，我不得不收拾一切，所以这不是我的想偷懒的情况。我只是被告知，如果你强迫腾出了那么你的对象将存储它可能会导致不好的东西。有人告诉我，让垃圾回收器做它。

那么，为什么我需要调用处理？ （我的猜测是，这是因为的TextWriter 打盘。）

有没有我需要小心的对象列表？ （或者一个简单的方法来知道什么时候我需要调用处理？）

解决方案

您是更正为正确写入代码GC最终将清理本地资源。该对象将有一个终结，和定稿期间将腾出必要的本地资源。

然而，当发生这种情况是非常不确定性。此外，它是一个有点倒退，因为你使用的用来处理管理内存来管理本地资源的一种手段GC。这导致了有趣的情况，并可能导致本土资源活路比预期更长的时间，导致情况下

• 文件打开后不久他们不再使用
• 资源句柄可以跑出来，因为GC没有看到足够的内存压力，迫使一个集合，因此运行终结

在使用/ Dispose模式决定增加原生资源的清理和消除这些问题。

I asked a question about this method:

// Save an object out to the disk public static void SerializeObject<T>(this T toSerialize, String filename) { XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType()); TextWriter textWriter = new StreamWriter(filename); xmlSerializer.Serialize(textWriter, toSerialize); textWriter.Close(); }

in the response I got this as an added remark:

Make sure you always dispose disposable resources such as streams and text readers and writers. This doesn't seem to be the case in your SerializeObject method.

So, I can tell that this is going to seem super lame for someone who has been coding C# for a year or two, but why do I have to dispose it?

Is see that testWriter has a dispose method, but shouldn't garbage collection take care of that? I came from Delphi to C#. In Delphi I had to clean up everything, so this is not a case of me wanting to be lazy. I just was told that if you force freeing up the memory that your objects take then it can cause bad stuff. I was told to "Just let the garbage collector do it".

So, why do I need to call dispose? (My guess is that it is because textWriter hits the disk.)

Is there a list of objects I need to be careful with? (Or an easy way to know when I need to call dispose?)

解决方案

You are correct that for properly written code the GC will eventually clean up the native resources. The object will have a finalizer, and during finalization will free up the necessary native resources.

However when this happens is very non-deterministic. Additionally it's a bit backwards because you're using the GC which designed to handle managed memory as a means to manage native resources. This leads to interesting cases and can cause native resources to stay alive much longer than anticipated leading to situations where

• Files are open long after they are no longer used
• Resource handles can run out because the GC doesn't see enough memory pressure to force a collection and hence run finalizers

The using / dispose pattern adds determinism to the cleanup of native resources and removes these problems.