The type or namespace name `Ports' does not exist in the namespace `System.IO'. Are you missing an assembly reference?

 The type or namespace name `Parity' could not be found. Are you missing an assembly reference?

The type or namespace name `StopBits' could not be found. Are you missing an assembly reference?

 The type or namespace name `SerialPort' could not be found. Are you missing an assembly reference?

导入后产生报错提示什么IO文件不可用

经上网百度后问题解决

解决办法：

.NTE 2.0Subset 这个是报错选项

正确操作，选择 上面的 .NET 2.0 问题解决.

记录一下留作以后方面查找。