What is the difference between 'protected'

Question

Can someone please elaborate me the difference between 'protected' and 'protected internal' modifiers in C#? It looks they behave in same manner.

Answer 1

Protected Member

Protected Member of a class in only available in the contained class (in which it has been declared) and in the derived class within the assembly and also outside the assembly.

Means if a class that resides outside the assembly can use the protected member of the other assembly by inherited that class only.

We can exposed the Protected member outside the assembly by inherited that class and use it in the derived class only.

Note: Protected members are not accessible using the object in the derived class.

Internal Member

Internal Member of a class is available or access within the assembly either creating object or in a derived class or you can say it is accessible across all the classes within the assembly.

Note: Internal members not accessible outside the assembly either using object creating or in a derived class.

Protected Internal

Protected Internal access modifier is combination Protected or Internal.

Protected Internal Member can be available within the entire assembly in which it declared either creating object or by inherited that class. And can be accessible outside the assembly in a derived class only.

Note: Protected Internal member works as Internal within the same assembly and works as Protected for outside the assembly.

Answer 2

protected can be used by any subclasses from any assembly.

protected internal is everything that protected is, plus also anything in the same assembly can access it.

Importantly, it doesn't mean "subclasses in the same assembly" - it is the union of the two, not the intersection.

Answer 3

You can find the difference in below table based accessibility is yes,

Answer 4

Protected internal best suites when you want a member or type to be used in a derived class from another assembly at the same time just want to consume the member or type in the parent assembly without deriving from the class where it is declared. Also if you want only to use a member or type with out deriving from another class, in the same assembly you can use internal only.

Answer 5

I have read out very clear definitions for these terms.

Protected : Access is limited to within the class definition and any class that inherits from the class. The type or member can be accessed only by code in the same class or struct or in a class that is derived from that class.

Internal : Access is limited to exclusively to classes defined within the current project assembly. The type or member can be accessed only by code in same class.

Protected-Internal : Access is limited to current assembly or types derived from containing class.

Answer 6

In practice, about methods:

protected - accessible for inherited classes, otherwise private.

internal - public only for classes inside the assembly, otherwise private.

protected internal - means protected or internal - methods become accessible for inherited classes and for any classes inside the assembly.