The event DataReceived is trigger by the serialport when have some data to read, even Eof character is received. Tipicaly this event is used to get that veri and start a process with it or store. For example, the serialport read a barcode and find it on the database. https://rowanrmcwj.tinyblogging.com/düşünceler-hakkında-bilmek-c-serialport-nedir-69435221