C # 0911

Class Library:

To put it bluntly, it is to let others call you to write the method, and do not let others see how you achieve.

If there is a function you do not do and need help from others, then your colleague can help you write a class and then you call the method in this class to complete your project.

1. C # source code files, including in their own projects

2. Class library,. dll

Advantages: You write a method that others do not see the implementation process, strong confidentiality

Cons: If you write a method with errors, others cannot change

---------------------------------------------------------delegate: A pointer that can be understood as a function

Delegate-Defining keywords

Declares the delegate type public delegate int Firstdel (int aaa, int bbb);

Create delegate variable, assign value, function point to Firstdel f1 = new Jiajian (). Jia;

int c = F1 (10, 20);

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var: universal type

Object: base class for all types

As: type conversion, if the conversion is unsuccessful, does not error, but returns a null

is: Determines whether a variable/object is a certain type, returns a bool value

Generic collection: List<t>

A set of fixed-length, invariant types

C # 0911