是否有一个等同于.NET 4.5：Storagefile.Openasync [英] Is there a .NET 4.5 equivalent to: Storagefile.Openasync

问题描述

我爱上了异步和等待，但我不知道如何等待一个文件，而无需使用Task.Run开放。似乎是在WRT API >。哪里是.NET 4.5相同呢？我问，因为如果我在远程机器上访问UNC共享这有阻止了很长的时间，如果机器被关闭或不响应由于某种原因，网络请求的潜力。这似乎是这么大了点。

 使用（的FileStream流=等待Task.Run（（）=＆gt;新建的FileStream（@C：\ TEMP \的text.txt，FileMode.OpenOrCreate，FileAccess.Read， FileShare.Read，4096，真正的）））
{
  byte []的bytesToRead =新的字节[stream.Length]
  等待stream.ReadAsync（bytesToRead，0，bytesToRead.Length）.ConfigureAwait（假）;
  返回bytesToRead;
}
 

解决方案

不幸的是，即使文件打开是异步的，在设备驱动程序级别，有一个异步打开文件没有的Win32 API。所以这就是为什么没有.NET同等学历;我不知道是肯定的，但我怀疑的WinRT API由它排队到线程池伪造异步操作。

所以，最好的办法是做一个类似的解决方法：使用 Task.Run 。我想换行所有的的FileStream code。在 Task.Run ，虽然。

I'm falling in love with async and await, however I cannot figure out how to await a file open without using Task.Run. There seems to be an API in WRT. Where is the .NET 4.5 equivalent? I ask because if i'm accessing a UNC share on a remote machine this has the potential to block for a very long time if the machine is down or not responding to network requests for some reason. It seems like such a big over site.

using (FileStream stream = await Task.Run(() => new FileStream(@"c:\temp\text.txt", FileMode.OpenOrCreate, FileAccess.Read, FileShare.Read, 4096, true)))
{
  byte[] bytesToRead = new byte[stream.Length];    
  await stream.ReadAsync(bytesToRead, 0, bytesToRead.Length).ConfigureAwait(false);
  return bytesToRead;
}

解决方案

Unfortunately, even though file opens are asynchronous at the device driver level, there is no Win32 API for an asynchronous file open. So that's why there's no .NET equivalent; I don't know for sure but I suspect that the WinRT API is faking an asynchronous operation by queueing it to the thread pool.

So, the best solution is to do a similar workaround: use Task.Run. I'd wrap all the FileStream code in Task.Run, though.

这篇关于是否有一个等同于.NET 4.5：Storagefile.Openasync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！