如何正确的使用StreamWriter类？ [英] how to use StreamWriter class properly?

问题描述

我有这样的代码中，我使用StreamWriter类的文件操作，有没有在此代码的任何问题，我需要把try catch块收盘应该在finally块？ ？或者这个代码就足够了。

 的StreamWriter SR =新的StreamWriter（streamFolder）; 
 sr.Write（详细信息）; 
 
 File.SetAttributes（streamFolder，FileAttributes.Hidden）; 
 sr.Close（）; 
  

解决方案

请告诉我你的代码错误？如果有些异常会在您关闭流发生，那么流将保持开放，以及系统资源不会被释放：

 的StreamWriter SR =新的StreamWriter（streamFolder）; 
 sr.Write（详细信息）; 
 //这里发生了一些异常
 File.SetAttributes（streamFolder，FileAttributes.Hidden）; 
 sr.Close（）; 
  

所以，你需要确保，该流将被关闭。这可以通过实现尝试...最后块：

 的StreamWriter SR =新的StreamWriter（streamFolder）; 
 
试
 {
 sr.Write（详细信息）; 
 //这里发生了一些异常
 File.SetAttributes（streamFolder，FileAttributes.Hidden）; 
} 
终于
 {
 sr.Close（）; 
} 
  

但StreamWriter的农具的 IDisposable的接口，这样可以让C＃编译器会自动为你做它用块包装作家使用到：

 使用（StreamWriter的SR =新的StreamWriter（streamFolder））
 {
 sr.Write（详细信息） ; 
 //这里发生了一些异常
 File.SetAttributes（streamFolder，FileAttributes.Hidden）; 
} 
  

这代码将被编译为：

 的StreamWriter SR =新的StreamWriter（streamFolder）; 
 
试
 {
 sr.Write（详细信息）; 
 //这里发生了一些异常
 File.SetAttributes（streamFolder，FileAttributes.Hidden）; 
} 
终于
 {
如果（SR！= NULL）
 sr.Dispose（）; 
} 
  





手工执行之间的唯一区别是无效检查和方法的Dispose 被调用，而不是关闭。但实际上，当你调用关闭（）或的Dispose（）相同的代码会被执行：

  this.Dispose（真）; 
 GC.SuppressFinalize（本）; 
  

您可以阅读更多的的 Dispose方法实现。

I have code like this where i am using StreamWriter class for file operation, is there any problems in this code ,do i need to put try catch block closing should be in finally block ? or this code is sufficient?

   StreamWriter sr = new StreamWriter(streamFolder);
                  sr.Write(details);

                  File.SetAttributes(streamFolder, FileAttributes.Hidden);
                  sr.Close();

解决方案

Whats wrong with your code? If some exception will occur before you close stream, then stream will stay open, and system resources will not be released:

StreamWriter sr = new StreamWriter(streamFolder);
sr.Write(details);
// some exception occurs here 
File.SetAttributes(streamFolder, FileAttributes.Hidden);
sr.Close();

So, you need to be sure, that stream will be closed. This could be achieved by try...finally block:

StreamWriter sr = new StreamWriter(streamFolder);

try 
{
   sr.Write(details);
   // some exception occurs here 
   File.SetAttributes(streamFolder, FileAttributes.Hidden);
}
finally
{
   sr.Close();
}

But StreamWriter implements IDisposable interface, so you can let C# compiler do it automatically for you by wrapping writer usage into using block:

using(StreamWriter sr = new StreamWriter(streamFolder)) 
{
   sr.Write(details);
   // some exception occurs here 
   File.SetAttributes(streamFolder, FileAttributes.Hidden);
}

This code will be compiled as:

StreamWriter sr = new StreamWriter(streamFolder);

try 
{
   sr.Write(details);
   // some exception occurs here 
   File.SetAttributes(streamFolder, FileAttributes.Hidden);
}
finally
{
   if (sr != null)
      sr.Dispose();
}

The only difference between manual implementation is null-check and method Dispose is called instead of Close. But actually when you call Close() or Dispose() same code will be executed:

this.Dispose(true);
GC.SuppressFinalize(this);

You can read more on Dispose method implementation.

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