C # ConfigurationManager There is no problem solving

When you do the serial communication, you need to use"ConfigurationManager"class, but after adding a "Using system.configuration" namespace, the compiler still complains, always showing that "ConfigurationManager" does not exist, but found"ConfigurationSettings"Can be used, but the notes on MSDN show the using the ConfigurationManager class, you can access configuration information for computers, applications, and users. This class replaces the "ConfigurationSettings" class that has been deprecated. "The beginning was suspected of being used. NET version is too old, but after viewing it, it is not, after looking closely at the MSDN technical documentation and discoveringthe "ConfigurationManager" class cannot be inherited., while also saying that the System.Configuration assembly is in System.Configuration.dll, so a reference to the solution is added to the System.Configuration, which solves the problem perfectly.

C # ConfigurationManager There is no problem solving