C#_event_ Events

-------------------Event---------------------------

1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Linq;4 usingSystem.Text;5 usingSystem.Threading.Tasks;6 7 namespace_01 Event Understanding8 {9     class ProgramTen     { One         Static voidMain (string[] args) A         { -Mp3player mp3 =NewMp3player (); -  theMP3. Afterpoweron + =Showon; -MP3. Beforepoweroff + =Showoff; -  - mp3. PowerOn (); + mp3. PowerOff (); - Console.readkey (); +         } A  at  -         Static voidShowon () -         { -Console.WriteLine ("Play boot animation"); -         } -  in        Static voidShowoff () -         { toConsole.WriteLine ("Play off animation"); +         } -  the     } *  $ Panax Notoginseng  -  the      Public classMp3player +     { A  the         //adding an event to the delegate before the delegate can be implemented only within the class +         //The delegate cannot be called outside of the class -  $         //that is, external can only register or delete the registered method cannot be called by itself $         //The call can only be inside the class. -  -         //that is, after the delegate adds an event, the outside of the class becomes an event only through the + =-= To register the Delete method cannot add () Execute the  -          Public EventAction Afterpoweron;Wuyi          Public EventAction Beforepoweroff; the  -          Public voidPowerOn () Wu         { -  AboutConsole.WriteLine ("boot ..."); $  -             //Post -Boot execution delegate can be understood as an event -             if(Afterpoweron! =NULL) -             { A Afterpoweron (); +             } the  - Musicstart (); $         } the  the          Public voidPowerOff () the         { the  - musicstop (); in  the                     //delegate invocation before shutdown if the delegate is not empty, this is understood here as an event the                     if(Beforepoweroff! =NULL) About                     { the Beforepoweroff (); the                     } theConsole.WriteLine ("turn off the machine"); +      -         } the Bayi         Private voidMusicstart () the         { theConsole.WriteLine ("Start playing music"); -         } -  the         Private voidmusicstop () the         { theConsole.WriteLine ("Music Stop ..."); the         } -     } the}

Event Understanding

C#_event_ Events