C#•3mo ago

✅ difference between internal and file access modifiers

the content on Microsoft Learn is a bit difficult to understand.

26 Replies

- internal: Only code in the same assembly can access this type or member. - file: Only code in the same file can access the type or member. an "assembly" is essentially a project, or dll file file is literally the same .cs file the file modifier is almost exclusive used with source generation, its not a modifier you would use when writing your own code

tommyOP•3mo ago

so when you say project, do you mean a collection of files?

Pobiega•3mo ago

no I mean a project C# is project based

tommyOP•3mo ago

yeah we have to create a Console App in .NET

Pobiega•3mo ago

projects can depend on other projects, but you cant access things that are internal from other projects sure, that would be an executable project.

tommyOP•3mo ago

then how do you define a project?

Pobiega•3mo ago

Pobiega•3mo ago

Calculator and CalculatorLibrary here are two different projects in the same solution the top one is likely a WinForms project and is the "startup project", while the bottom one is a class library that is used by the other project strictly speaking, a project is defined by the existance of a .csproj file in a directory anything under taht directory (including sub-directories) is considered part of that project

tommyOP•3mo ago

got it

Pobiega•3mo ago

Foo/
|-src/
  |-Foo.Web/
    |-Foo.Web.csproj
  |-Foo.Domain/
    |-Foo.Domain.csproj
|-test/
  |-Foo.Web.Tests/
    |-Foo.Web.Tests.csproj
  |-Foo.Domain.Tests/
    |-Foo.Domain.Tests.csproj
|-Foo.sln

Foo/
|-src/
  |-Foo.Web/
    |-Foo.Web.csproj
  |-Foo.Domain/
    |-Foo.Domain.csproj
|-test/
  |-Foo.Web.Tests/
    |-Foo.Web.Tests.csproj
  |-Foo.Domain.Tests/
    |-Foo.Domain.Tests.csproj
|-Foo.sln

as an example

tommyOP•3mo ago

hmm so this is a solution containing 4 projects?

Pobiega•3mo ago

correct the Foo.Web project is likely the startup project, probably an ASP.NET application of some sort Foo.Domain is a normal class library, while the two test projects are... well, test projects

tommyOP•3mo ago

got it, so if we want to limit the access of a type to a specific project, I am gonna use internal

Pobiega•3mo ago

yeah exactly then only code inside that project can use that type there is a way to intentionally expose internals to another project, and its almost exclusively used for testing

tommyOP•3mo ago

wow

Pobiega•3mo ago

you can in Foo.Domain.csproj declare that Foo.Domain.Tests should have access to internals so its controlled by the declaring project, not the consuming one

tommyOP•3mo ago

and just making sure if I know things correctly, a dll file is a file compiled to IL

Pobiega•3mo ago

yeah, but thats mostly an implementation detail and not all DLL files are compiled .NET projects, there might be native dlls too, in the case of a package like Sqlite

tommyOP•3mo ago

okay sprry i got a call inbetween

Pobiega•3mo ago

tommyOP•3mo ago

this was a very satisfying response thank you man

Pobiega•3mo ago

tommyOP•3mo ago

do you how to close this post?

Pobiega•3mo ago

/close

tommyOP•3mo ago

okay

Pobiega•3mo ago

then the bot takes care of it

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✅ difference between internal and file access modifiers