Example explanation of events and weak events

1 usingSystem;2 usingSystem.Windows;//Implementing a weak event requires referencing the WindowsBase assembly3 4 namespaceexample explanation of events and weak events5 {6     class Program7     {8         Static voidMain (string[] args)9         {Ten             vardealer =NewCardealer ();//This class contains an event handler, and a method for invoking it One  A             varMichael =NewConsumer ("Michael");//This class contains the name of a person and a method for responding to events, with the event argument type Carinfoeventargs -  -Weakeventmanager<cardealer, Carinfoeventargs> AddHandler (dealer,"Newcarinfo", Michael. Newcarishere); the             //Adding a connection registration to a static generic class of a weak event by using a static method -  -Dealer. Newcar ("Ferrari");//executing the event handler -  +             varSebastian =NewConsumer ("Sebas days"); -Weakeventmanager<cardealer, Carinfoeventargs> AddHandler (dealer,"Newcarinfo", Sebastian. Newcarishere); +  ADealer. Newcar ("Mei Soders"); at  -Weakeventmanager<cardealer, Carinfoeventargs> RemoveHandler (dealer,"Newcarinfo", Michael. Newcarishere); -             //The static method of a static generic class for a weak event removes both connection registrations -  -Dealer. Newcar ("Red Bull Competition"); -  in Console.readkey (); -         } to     } +  -     //The general idea of the event system the     //Activating Event Response Methods (2nd model, methods of receiving reminders and data) by Event reminder Delegate (event handler) (1th model, managing parameter definitions and event delegates for method registrations) *     //there should be a uniform parameter agreement between the two to pass the data, this parameter is the event parameter (3rd model, the class containing the data) $     //their entirety is invoked by an instance of the generic event handler eventhandler<teventargs>, using EventHandler (object sender, Teventargs e)Panax Notoginseng     //Sender is a publisher that passes information about the publisher, and E is the event argument that contains its custom data (usually attributes) -  the     //the idea of a weak event system (based on the event system) +     //define a mediator to receive reminders (from the event handler) and send reminders (to event response methods) to manage the registration status of both connections A     //teventargs> static method to manage registration status through static generic class weakeventmanager<teventsource of weak events the     //use static methods AddHandler and RemoveHandler to add or cancel registrations +     //Method Example: Weakeventmanager<cardealer, Carinfoeventargs>. AddHandler (dealer, "Newcarinfo", Sebastian. Newcarishere); -     //Dealer is the class instance of the event handler, and "Newcarinfo" is the identifier (event delegate name) of the event handler, Sebastian. Newcarishere is an event response method for a class instance $     //benefit: Resolves a memory leak issue.  $  -  -      Public classConsumer the     //Model 2 contains the class of the event response method, or the listener -     {Wuyi         Private stringname; the  -          PublicConsumer (stringname) Wu         { -              This. Name =name; About         } $  -  -          Public voidNewcarishere (Objectsender, Carinfoeventargs e) -         //This is an event response method, and the second parameter determines the event argument type to match the event handler for the same parameter A         { +Console.WriteLine ("{0}: New arrivals for car {1}! Event performer: {2}", name, E.car, sender. ToString ()); the         } -     } $  the      Public classCarinfoeventargs:eventargs the     //Model 3 This is an event parameter class that is used in both event handlers and event response methods to pass data in a uniform type the     //It stores the data in the Car property. the     { -          PublicCarinfoeventargs (stringcar) in         //the constructor of the event argument receives a string type parameter and stores it as a property of Car the         { the              This. Car =car; About         } the  the          Public stringCar {Get;Private Set; } the     } +  -      Public classCardealer the     //Model 1 contains the class of the event handler, or is called the publisherBayi     { the          Public EventEventhandler<carinfoeventargs>Newcarinfo; the         //This is an event reminder delegate, called the event handler, which needs to define the event argument type -  -          Public voidNewcar (stringcar) the         { theConsole.WriteLine ("Auto Supplier: New Car {0}", car); the  the raisenewcarinfo (car); - Console.WriteLine (); the         } the  the         protected Virtual voidRaisenewcarinfo (stringcar)94         //This is a common method that requires receiving a string type parameter the         //and passes the string argument to the event argument, and then executes the event through the event handler with the same event type the         { theEventhandler<carinfoeventargs> Newcarinfo =Newcarinfo;98             if(Newcarinfo! =NULL) About             { -Newcarinfo ( This,NewCarinfoeventargs (car));101             }102         }103     }104}

Example explanation of events and weak events