Issues related to C ＃ delegation and events

1. The essence of entrustment

Everyone should know that the function is called to find the first address of the function , Then call , The essence of a delegate is to record the first address of a function , Just like the essence of calling a function .

2. The initialization of delegates is different from that of custom types

1. entrust

Delegates can be assigned to NULL Under the circumstances , To assign the function name , It can be called normally , Unwanted new.

2. Custom type （ Reference type ）

must do new To assign a value to a member element , Why? ？ for example :

class Test 
{
        public int a;
}
Test s=null;
s.a=100;
Console.WriteLine(s.a);

Will report an error directly , Because it is not initialized , No memory space has been requested for the change variable , Only variable names have content space .
reason : Delegation can be dispensed with new The reason is that the variable name can be directly assigned to the first address of the function , You can go directly to .

event

1. Events can only be defined within a class , Intra class call , Because its real writing is private , Cannot call directly