week 6

delegate

i'm always struggling with new ideas,now i'd like to show you a piece of code:

using System;
using System.Collections.Generic;
using System.Text;

namespace Delegate {

     public delegate void GreetingDelegate(string name);
        class Program {

           private static void EnglishGreeting(string name) {
               Console.WriteLine("Morning, " + name);
           }

           private static void ChineseGreeting(string name) {
               Console.WriteLine("早上好, " + name);
           }

           private static void GreetPeople(string name, GreetingDelegate MakeGreeting) {
               MakeGreeting(name);
            }

           static void Main(string[] args) {
               GreetPeople("Jimmy Zhang", EnglishGreeting);
               GreetPeople("张", ChineseGreeting);
               Console.ReadKey();
           }
        }
    }

output:

Morning, Jimmy Zhang
早上好, 张

regular expression
extract pattern
by using function:
whether the string matches the regular expression
substring
modify and change a string automatically

literals :character to match
metacharacters :command

namespace:System.Text.RegularExpressions
\S non space
\s space
+ one or more

regex
IP mail address time web site

exception
bug programmer's mistake
error user action
exception predictable but unpreventable problems try catch

throw catch
System.Exception
can't be solved throw to its parent
skip the code after
catch block
the first one is the most specified
the last one is the most general one

delegate event
contain the address of method
pointer of method
use method when encounter the pointer
delegate sample()
public int method()
sample.m =new sample(instance.method)

lambda expression=＞

asynccallback
main is running while the date hasnot ready

await a method
intelligently pack the rest of the method into asynccallback

into a new thread

when the data is ready it comes back and continue to execute

async await