C # (. NET) Essays

1. Access permission modifiers

Private: A privately owned member that can be accessed within a class.

Protected: A protected member that can be accessed within the class and in the inheriting class.

Public: Common members, completely public, without access restrictions.

Internal: Can be accessed in the current assembly.

The default modifier for the class is internal

2. Nullable type (Nullable)

Grammar:< data_type>? <variable_name> = null;

　　　　int? num1 = null;

int? num2 = ;

3 Class (abstract)

A) Abstract classes cannot be instantiated directly.

b) can contain abstract methods, ordinary classes cannot.

4.Static Static

A) in a non-static class, there can be instance members or non-static members

b) cannot have instance members in a static class

c) When you invoke an instance member, you need to use the object name. Instance members;

When you call a static member, you need to use the class name. static members;

C # (. NET) Essays