当文件被锁定时，在C＃中模拟等待File.Open [英] Emulate waiting on File.Open in C# when file is locked

问题描述

我本质上和这张海报有相同的问题，但是在C＃中：等待，直到一个文件可用于阅读与Win32

更多信息：我们有代码调用 File.Open 在我们的一个项目中，当文件已经被另一个进程（编辑：或线程）打开时偶尔会死掉：

  FileStream stream = File.Open（m_fileName，m_mode，m_access）; 
 / *做stream-type-stuff * / 
 stream.Close（）; 
  

File.Open 会抛出 IOException （它目前正悄悄地被吞下去），其 HResult 属性是 0x80070020 （ ERROR_SHARING_VIOLATION ）。

  FileStream stream = null; 
 while（stream == null）{
 try {
 stream = File.Open（m_fileName，m_mode，m_access，FileShare.Read）; 
} catch（IOException e）{
 const int ERROR_SHARING_VIOLATION = int（0x80070020）; 
 if（e.HResult！= ERROR_SHARING_VIOLATION）
 throw; 
 else 
 Thread.Sleep（1000）; 
 
 
做stream-type-stuff * / 
 stream.Close（）; 
  

但是， HResult 是受保护的成员 Exception ，无法访问 - 代码不能编译。有没有另外一种方式来访问 HResult ，或者也许是我可以用来做我想要的.NET的另一部分？

哦，最后一个警告，这是一个愚蠢的：我只能使用Visual Studio 2005和.NET 2.0。 解决方案

您可以在 catch 子句中调用 Marshal.GetHRForException（）来获取错误代码。不需要反思：

  using System.Runtime.InteropServices; 
 
 if（Marshal.GetHRForException（e）== ERROR_SHARING_VIOLATION）
 .... 
  

I have, essentially, the same problem as this poster, but in C#: Waiting until a file is available for reading with Win32

More information: we have code that calls File.Open in one of our projects, that occasionally dies when the file is already opened by another process (EDIT: or thread):

FileStream stream = File.Open(m_fileName, m_mode, m_access);
/* do stream-type-stuff */
stream.Close();

File.Open will throw an IOException (which is currently quietly swallowed somewhere), whose HResult property is 0x80070020 (ERROR_SHARING_VIOLATION). What I would like to do is this:

FileStream stream = null;
while (stream == null) {
    try {
        stream = File.Open(m_fileName, m_mode, m_access, FileShare.Read);
    } catch (IOException e) {
        const int ERROR_SHARING_VIOLATION = int(0x80070020);
        if (e.HResult != ERROR_SHARING_VIOLATION)
            throw;
        else
            Thread.Sleep(1000);
    }
}
/* do stream-type-stuff */
stream.Close();

However, HResult is a protected member of Exception, and cannot be accessed -- the code does not compile. Is there another way of accessing the HResult, or perhaps, another part of .NET I might use to do what I want?

Oh, one final caveat, and it's a doozy: I'm limited to using Visual Studio 2005 and .NET 2.0.

解决方案

You can call Marshal.GetHRForException() within the catch clause to get the error code. No need for reflection:

using System.Runtime.InteropServices;

if (Marshal.GetHRForException(e) == ERROR_SHARING_VIOLATION)
    ....

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