我如何知道文件已打开或正在使用？ [复制]

可能的重复：
有没有办法检查文件是否正在使用？ https://stackoverflow.com/questions/876473/is-there-a-way-to-check-if-a-file-is-in-use
检查文件是否打开 https://stackoverflow.com/questions/2987559/check-if-a-file-is-open

我如何知道文件已打开或正在使用。

public bool FileIsLocked(string strFullFileName)
        {
            bool blnReturn = false;
            System.IO.FileStream fs;
            try
            {
                fs = System.IO.File.Open(strFullFileName, FileMode.OpenOrCreate, FileAccess.Read, FileShare.None);
                fs.Close();
            }
            catch (System.IO.IOException ex)
            {
                blnReturn = true;
            }
            return blnReturn;
        }

我发现上面的代码不能正常工作

摘自这里：有没有办法检查文件是否正在使用？ https://stackoverflow.com/questions/876473/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;
    }