C#检查文件是否打开 [英] c# check if file is open

问题描述

我需要验证是否打开了特定文件，以防止复制该文件.

I need to verify if specific file is open to prevent the copy of that file.

我尝试了很多例子，但是任何例子都行不通！我尝试例如:

I try lot of examples but any doesn't work! I try, for example, this:

protected virtual bool IsFileLocked(FileInfo file)
{
    FileStream stream = null;

    try
    {
        stream = file.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.None);
    }
    catch (IOException)
    {
        //the file is unavailable because it is:
        //still being written to
        //or being processed by another thread
        //or does not exist (has already been processed)
        return true;
    }
    finally
    {
        if (stream != null)
            stream.Close();
    }

    //file is not locked
    return false;
}

我需要方向...我在哪里失败?建议?

I need orientation... where am I fail? suggestions?

推荐答案

您可能会因此而遭受线程竞争的状况，有文献记载将此事用作安全漏洞.如果您检查文件是否可用，然后尝试使用它，那您可能会抛出该文件，恶意用户可能会使用该文件来强制和利用您的代码.

You can suffer from a thread race condition on this which there are documented examples of this being used as a security vulnerability. If you check that the file is available, but then try and use it you could throw at that point, which a malicious user could use to force and exploit in your code.

您最好的选择是try catch/最终尝试获取文件句柄.

Your best bet is a try catch / finally which tries to get the file handle.

try
{
   using (Stream stream = new FileStream("MyFilename.txt", FileMode.Open))
   {
        // File/Stream manipulating code here
   }
} catch {
  //check here why it failed and ask user to retry if the file is in use.
}

或

查看其他选项

https://stackoverflow.com/a/11060322/2218635

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