types - How to add my own datatype in C# program? -

refers to "int32" class like "int", "string" means "string" class. How to see "ABC" datatype for my "ABC" class?

Your "class" is a data type.

The examples given by you are the difference between the name of the CLR data type and the C # datatype names. They are nicknames, the CRR int32 and C # string maps for the CLR string, the C # int maps.

You can make your own nickname using "Xyx = Abc". You must do this in each source file, so this is not useful.