Part 2

Classes and their access modifiers

Protected or protected

Let’s start with an easy one.

In VB_Class_Libraby_2

Protected Class Class1

End Class```
Which gives us a very interesting error message.

> Protected types can only be declared inside of a class.

Which seems more than logical.

Now let’s see what C# has to say about this.

In C\_Class\_Librabry_2.

```csharp
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Class_Library_2
{
    protected class Class1
    {
    }
}

And it seems to come to the same conclusion.

Elements defined in a namespace cannot be explicitly declared as private, protected, or protected internal

In VB_Class_Library_2

Public Class Class1
    Protected Class Class1_1

    End Class
End Class

And this.

In C_Class_Library_2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Class_Library_2
{
    public class Class1
    {
        protected class Class1_1
        {
        }
    }
}

Should work just fine.

We can now also state that the protected class will only be available to its parent or to subclasses of the parent.

So if I do this:

In VB_Class_Library_2

Public Class Class1
    Protected Class Class1_1

    End Class
End Class

Public Class Class2
    Inherits Class1

    Public Sub New()
        Dim _Class1 As New Class1_1
    End Sub
End Class

In C_Class_Library_2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Class_Library_2
{
    public class Class1
    {
        protected class Class1_1
        {
        }
    }

    public class Class2 : Class1
    {
        public Class2()
        {
            Class1_1 class1_1;
        }
    }
}

But I am digressing. I was going to talk about the differences.

Friend or internal

Here is the biggest difference. They decided to use a different keyword for the same thing, neither of them seem to catch the real essence of what the keyword is trying to say. I can say the same for protected BTW, but I think that would have been hard. A Friend or an Internal class can only be used in the same assembly and not by a referencing assembly.

In VB_Class_Library_2

Friend Class Class1

End Class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Class_Library_2
{
    internal class Class1
    {
    }
}

needless to say, we will get error messages if we try to call them from another project/assembly.

In C_Console

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Console
{
    class Program
    {
        static void Main(string[] args)
        {
            C_Class_Library_2.Class1 class1 = new C_Class_Library_2.Class1();
        }
    }
}

You actually get three error messages on this one line of code (Well done).

2 times this one.

‘C_Class_Library_2.Class1’ is inaccessible due to its protection level

And one of these.

The type ‘C_Class_Library_2.Class1’ has no constructors defined

In VB_Console

Module Module1

    Sub Main()
        VB_Class_Library_2.Class1 = New VB_Class_Library_2.Class1()
    End Sub

End Module

Here I only get 2 error messages.

2 times

‘VB_Class_Library_2.Class1’ is not accessible in this context because it is ‘Friend’.

Protected Friend or protected internal

This is even more restrictive because it makes it protected and Friend/internal at the same time. I won’t go deeper into this because we will get more of the same.

Public or public

This is the simplest one of all. It makes it so you can use your class everywhere and it is the same for everyone.

No Access modifiers

This is the most curious one. Do both languages default to the same access modifier when you leave it out?

In C_Class_Library_2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Class_Library_2
{
    class Class1
    {
    }
}

In C_Console

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace C_Console
{
    class Program
    {
        static void Main(string[] args)
        {
            C_Class_Library_2.Class1 class1 = new C_Class_Library_2.Class1();
        }
    }
}

And now run this and see what error messages you get.

Yes, you get the exact same ones as for Friend/Internal, so we now know that csharp defaults to internal when you specify no access modifier.

Now let’s see what VB.Net gives us.

In VB_Class_Library_2.

Class Class1

End Class

and

In VB_Console

Module Module1

    Sub Main()
        VB_Class_Library_2.Class1 = New VB_Class_Library_2.Class1()
    End Sub

End Module

And the error message tells us immediately that it also considers it as friend.

Next up Namespaces and variable declaration.