#region 判断文件是否被占用
        [DllImport("kernel32.dll")]
        public static extern IntPtr _lopen(string lpPathName, int iReadWrite);
        [DllImport("kernel32.dll")]
        public static extern bool CloseHandle(IntPtr hObject);
        public const int OF_READWRITE = 2;
        public const int OF_SHARE_DENY_NONE = 0x40;
        public readonly IntPtr HFILE_ERROR = new IntPtr(-1);
        private bool IfIsOccupied(string filePath)
        {
            if (File.Exists(filePath))
            {
                IntPtr vHandle = _lopen(filePath, OF_READWRITE | OF_SHARE_DENY_NONE);
                if (vHandle == HFILE_ERROR)
                {

                    return false;
                }
                CloseHandle(vHandle);
                //File.Delete(filePath);
            }
            return true;
        }
        #endregion