Check if file is in use [duplicate]

问题

Hi guys I need some help. I'm trying to open a textfile on a servern from multiple clients at the same time so I'm not locking the file when reading from it. Like this:

new StreamReader(File.Open(logFilePath, 
                       FileMode.Open, 
                       FileAccess.Read, 
                       FileShare.ReadWrite))

Now I'm trying to check if this file is used by any of the clients (because I want to write something new to it), but since I'm not locking it when reading from it I don't know how to do this. I can't try to open and catch an exception because it will open.

回答1:

I can't try to open and catch an exception because it will open

Why ? It's a valuable option to work in that way.

By the way you can also create a some empty predefined file, say "access.lock", and others, in order to understand if the actual file is locked check on lock file presence:

if(File.Exist("access.lock")) 
  //locked 
else
  //write something

回答2:

Do you can try this?

Or watch this question already asked here ->Is there a way to check if a file is in use?

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;
}

来源：https://stackoverflow.com/questions/16031145/check-if-file-is-in-use

标签

file

locking