/// <summary>
 /// 是否可以执行打印命令
 /// </summary>
 /// <returns></returns>
 private bool OnCanExecutePrintCommand()
 {
     if (Equals(DeviceServerInfoList, null) || !DeviceServerInfoList.Any())
     {
         return(false);
     }
     else
     {
         return(true);
     }
 }