Class Accessibility Matrix Diagram

What is Default accessibility of class

• Internal

Difference between Internal and Protected Internal

• Look above image for clarification

1. Public

• Accessibility: The class is accessible from any other class or assembly.
• Usage: When you want the class to be widely accessible.

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// Public class can be accessed from anywhere
public class PublicClass
{
    public string Name { get; set; }
}

2. Internal

• Accessibility: The class is accessible only within the same assembly (project).
• Usage: When you want to limit access to within the assembly, which is useful for encapsulation.

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// Internal class can only be accessed within the same assembly
internal class InternalClass
{
    public string Name { get; set; }
}

3. Protected

• Accessibility: The class itself cannot be protected, but its members can be. A class can be derived from a base class with protected members.
• Usage: When you want to allow access to members only in derived classes.

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public class BaseClass
{
    protected string Name { get; set; }
}

public class DerivedClass : BaseClass
{
    public void PrintName()
    {
        // Accessing protected member from the base class
        Console.WriteLine(Name);
    }
}

4. Private

• Accessibility: A class itself cannot be private, but its members can be. Private members are only accessible within the same class.
• Usage: When you want to restrict access to the class members to only within the class itself.

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public class MyClass
{
    private string Name { get; set; }

    public void SetName(string name)
    {
        Name = name;
    }
    
    public string GetName()
    {
        return Name;
    }
}

5. Protected Internal

• Accessibility: The class or member is accessible within the same assembly and also to derived classes in other assemblies.
• Usage: Useful for situations where you want to expose class members to derived classes or within the assembly.

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public class MyClass
{
    protected internal string Name { get; set; }
}

6. Private Protected

• Accessibility: The class or member is accessible within the same class or in derived classes that are in the same assembly.
• Usage: A more restrictive version of protected internal, useful for fine-grained access control.

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public class MyClass
{
    private protected string Name { get; set; }
}