Modifiers in C#

Access Modifiers: Access modifiers are keywords used to specify the declared accessibility of a member or a type. This section introduces the four access modifiers: public, protected, internal & private

The following five accessibility levels can be specified using the access modifiers:

• public: Access is not restricted.
• protected: Access is limited to the containing class or types derived from the containing class.
• Internal: Access is limited to the current assembly.
• protected internal: Access is limited to the current assembly or types derived from the containing class.
• private: Access is limited to the containing type.

Other Modifiers: 

• abstract - Indicates that a class is intended only to be a base class of other classes.
• const - Specifies that the value of the field or the local variable cannot be modified.
• event - Declares an event.
• extern - Indicates that the method is implemented externally.
• new - Hides an inherited member from a base class member.
• override - Provides a new implementation of a virtual member inherited from a base class.
• partial - Defines partial classes, structs and methods throughout the same assembly.
• readonly - Declares a field that can only be assigned values as part of the declaration or in a constructor in the same class.
• sealed - Specifies that a class cannot be inherited.
• static - Declares a member that belongs to the type itself instead of to a specific object.
• unsafe - Declares an unsafe context.
• virtual - Declares a method or an accessor whose implementation can be changed by an overriding member in a derived class.
• volatile - Indicates that a field can be modified in the program by something such as the operating system, the hardware, or a concurrently executing thread.