Inheritable only inside assembly in C#

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In C# Is there way to specify a class to be inherited only by a class present in the same assembly and for other assemblies should behave like a public sealed type.

Inheritance in C#, Internal members are visible only in derived classes that are located in the same assembly as the base class. They are not visible in derived� Inheritance (C# Programming Guide) 02/07/2020; 7 minutes to read +7; In this article. Inheritance, together with encapsulation and polymorphism, is one of the three primary characteristics of object-oriented programming.

The language itself doesn't have anything that makes this easy, but you should be able to do this by making your constructors internal. If you do this, however, you won't be able to new it up from external assemblies, so you'll have to add a factory method.

public class Foo
    internal Foo()

    public Foo Create()
        return new Foo();

Here's an alternative that lets you new up the class in external assemblies

public sealed class Foo : FooBase


public class FooBase
    internal FooBase() { }

One question you might ask yourself, however, is exactly why you want the class to be sealed. Sometimes it's inevitable, but I have seen the sealed keyword get abused so often that I thought I'd bring it up. Often, developers will seal classes because they are overprotective of their code. Most of the time, if a class is well designed, it doesn't need to be sealed.

Access Modifiers, Classes and structs declared directly within a namespace (in other words, that or private protected because structs don't support inheritance. directly within a namespace can be public or internal and, just like classes and� What Is An Assembly In C# Summary. In this tutorial, we learned how Visual Studio and the C# compiler will compile our source code into an assembly. The assembly name will have the same name as the project. The resulting assembly will have an .exe or .dll extension depending on if you were building a program to execute directly, or a class library.

If your class is abstract, there's a very simple way to do it:

public abstract class Foo {
    internal abstract void DoNothing();
    // ... other members

Now although your class and most members are public, the internal abstract member makes it impossible to derive from the class outside your assembly.

C# inherit from a class in a different DLL, Types and members declared as internal are only visible within their own assembly. In your project you must add a reference to the other assembly or project in� The private key is our secret and stays with us. The public key token is stored along with the public key inside the Global Assembly's manifest. This process is called Signing the assembly. The CLR needs the public key to decrypt the token to verify the file but not other way around.

To answer the question 10 years later (I was searching for this same solution, so I figure it'd be useful to write down in case anybody else has the same problem in the future), the issue has since been addressed natively (albeit indirectly), with the "private protected" access modifier, introduced in C# 7.2.

This modifier only allows access if it is within the same assembly, and derived from the base class. Apply it to the constructor, and it cannot be derived outside the current assembly. An aside, if you can get away with "internal" and/or metadata, do it, as this requires C# 7.2, which may break compatibility with older devices or applications. Also note that the error produced by this (cannot access constructor due to protection level) is not the same as you would get trying to derive a sealed class (cannot derive a sealed class), but the end result is the same.

#620 – Inherit from a Class In A Different Assembly, You inherit from the Dog class just like you inherit from a class within your own program. 1. 2. 3. 4. 5. 6. 7. 8. The second example shows how to use the Version property to specify the assembly version when you emit a dynamic assembly. Example 1. The following example retrieves and displays the version numbers of the currently executing assembly and the assembly that contains the String class.

The only way I can think would be to use a public wrapper on an internal class, probably with a common interface:

public interface IFoo

internal class Foo : IFoo

public sealed class PublicFoo : IFoo
    private Foo m_Foo = new Foo();

Identifying all Subclasses of a Class, to identify all of the subtypes of a given class that exist within an assembly. When an unknown assembly is provided, you might need to find all types that inherit from a Occasionally, you might only want to find the direct descendants of a type. NET FrameworkAlgorithms and Data StructuresAudioC#� .assembly <assembly name> Specifies the assembly name..hash algorithm <int32 value> Specifies the hash algorithm used..ver <version number> Specifies the version number of the assembly..module <file name> Specifies the name of the modules that make up the assembly. In this example, the assembly consists of only one file..subsystem <value>

C# Access Modifiers , CSharp Access Specifiers, using System; namespace ConsoleApplication1 { class PrivateAccess { private The scope of the accessibility of private access members limited only inside the that how a protected variable and function can access from inherited calss. There is a concept of Friend Assembly in C#. It allows us to access the internal classes in other assembly. Note : Only Internal classes can be exposed to other assembly. Private classes can not be made available outside the assembly. This can be applied at assembly level only. We need to apply InternalsVisibleToAttribute to assemblyinfo.cs.

C# Basics - Access Modifiers in C#, Learn about Access Modifiers in C#, how to use them, what are the Objects that implement private access modifier are accessible only inside a We will talk in more detail about inheritance in module 2 about object-oriented programming. object is accessible only inside its own assembly but not in other assemblies: C#. A Strong-Named assembly ensures that an assembly cannot be tampered with. Global Assembly Cache (GAC) A strong-named assembly consists of a unique version number that can only exist more than once with the same name. The GAC is a machine-wide independent location that allows Strong-Named assemblies to register.

OOP Series #2: Understanding Access Specifiers In C#, protected: plays a role only when inheritance is used. A protected internal will be accessible within the assembly due to its internal flavor and�

  • +1 - For your thoughts. But the problem is I need it for ConfigurationElementCollection so, I don't think constructor cannot be made internal in my case
  • Try the second solution, create a base class that has internal constructors, and then implement it with a sealed class that has public constructors.
  • I would suggest naming the method PreventExternalInheritance or something similar.
  • It would be nice if you could flag it with some sort of attribute, like you do with obsolete code.
  • Well, you can always add to <summary> comment: "This class cannot be inherited."
  • @Michael answer ( provides the same solution
  • It is technically correct, but I suspect that Ramesh probably already intuited that. It's more helpful to provide potential workarounds.