157 recommendations for writing high-quality code to improve C # programs--Recommendation 41: Implementing a standard event model

Recommendation 41: Implementing a standard event model

In the previous recommendation, we implemented a file transfer class Fileuploader with event notification. Although the requirements have been met, but do not conform to C # coding specifications, view EventHandler's prototype declaration:

 Public Delegate void EventHandler (object sender, EventArgs e);

We should know a few of the specifications Microsoft defines for the event model:

• The name of the delegate type has EventHandler ended;
• The return value of the delegate prototype is void;
• The delegate prototype has two parameters: Sender represents the event trigger, and E represents the event argument;
• The name of the event argument ends with EventArgs.

To modify Fileuploader to conform to the C # Programming specification, you first need to provide a Fileuploadedeventargs class to hold the progress information:

    classFileuploadedeventargs:eventargs { Public intfileprogress {Get;Set; } }    classFileuploader { Public EventEventhandler<fileuploadedeventargs>fileuploaded;  Public voidUpload () {Fileuploadedeventargs e=NewFileuploadedeventargs () {fileprogress = - };  while(E.fileprogress >0)            {
　　　　　　　　　 //Transfer code, omit e.fileprogress--; if(fileuploaded! =NULL) {fileuploaded ( This, E); }            }        }    }

Calling code:

        Static void Main (string[] args)        {            Fileuploader f1=new  fileuploader ();             + = f1_fileuploaded;
F1. Upload ();        }         Static void f1_fileuploaded (object  sender, Fileuploadedeventargs e)        {            Console.WriteLine (e.fileprogress);        }

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157 recommendations for writing high-quality code to improve C # programs--Recommendation 41: Implementing a standard event model