C#•2d ago

✅ Public class in C#

Hello guys, sorry to disturb you all; can someone explain when do we use a "public class" and non-public class in C# pls. For example, consider the following code:

C#

using System;

namespace Learning
{
    class Program
    {
        static void Main(string[] args)
        {
            . . .
        }

        
    }
}

C#

using System;

namespace Learning
{
    class Program
    {
        static void Main(string[] args)
        {
            . . .
        }

        
    }
}

I didn't use TLS. I use write "class"; does it have a default value? like private class / public class? if so, what do these values represent pls. When should we use private/ public or just write class and why? Say when we create new classes, like a class for person etc, it matters if we put private/public or anything? Also, if a class is public, it can only have one public class within the same file ? Now, consider the code above, can I create multiple classes within that same file? Like when after the class Program ending curly braces, I juste write a class, named "class Person" ? Is that good practice/recommended? Sorry that's a lot of questions

17 Replies

Angius•2d ago

C# always defaults to the lowest access In context of a project, the classes being public/internal/private don't really matter all that much Those access modifiers are there should you want to access those classes from another project

FakerOP•2d ago

yeah I see, here in the code, it defaults to which level of access ? private?

Angius•2d ago

Yep

Angius•2d ago

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/access-modifiers

Access Modifiers - C#

All types and type members in C# have an accessibility level that controls whether they can be used from other code. Review this list of access modifiers.

FakerOP•2d ago

yeah I see, it's there just if we want to reuse classes in another project Now, can I create multiple classes within that same file? Like when after the class Program ending curly braces, I juste write a class, named "class Person" ? Is that good practice/recommended?

Angius•2d ago

You can have multiple classes per file, sure Though the convention is one class per file

FakerOP•2d ago

yep I see, if we have multiple class per file, we can't use the TLS anymore ?

Angius•2d ago

You can

FakerOP•2d ago

oh ok, just for the new class I want to create, a just need to specify sommething like class Person { . . .} Something like that?

C#
Console.WriteLine("Hello World !");
class Person
{
  . . .
}

C#
Console.WriteLine("Hello World !");
class Person
{
  . . .
}

Angius•2d ago

$tias

MODiX•2d ago

https://images-ext-1.discordapp.net/external/CO2vsU2aXbRqYy1RdewOYnkBq1nGFBjdbjlNgjvG67A/https/media.discordapp.net/attachments/364492811489509376/964064233035816990/unknown.png?width=543&height=257

Angius•2d ago

But yes

FakerOP•2d ago

ok ok thanks ! by the way, why not declare all classes/method/everything as public? Because only the developer will have access to source code, no ? (well I know it's not done but why can't we ?)

Angius•2d ago

You can

FakerOP•2d ago

yeah, but is it bad practice or it depends on the use case?

Angius•2d ago

Eh, depends how strict you want to be It's considered a good practice to make classes internal by default Personally, outside of libraries, I don't care much

FakerOP•2d ago

yeah I see noted, thanks !!

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✅ Public class in C#

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