判断文件是否正在使用

public bool IsFileInUse(string fileName)
        {
            bool inUse = true;
            if (File.Exists(fileName))
            {
                FileStream fs = null;
                try
                {
                    fs = new FileStream(fileName, FileMode.Open, FileAccess.Read,FileShare.None);
                    if (fs.CanWrite)
                    {
                        inUse = false;
                    }
                    else
                        inUse = true;
                    inUse = false;
                }
                catch
                {
                    // exception....
                }
                finally
                {
                   if (fs != null)

                        fs.Close();
                }
               return inUse;//by yl  true表示正在使用,false没有使用

            }
            else
            {
               return false;//文件不存在,肯定没有被使用
            }

        }