使函数可以从同一项目中的其他类访问，但不能在另一个项目中访问

Question

I have a project called Category_Helper_Project .

Within this project are two relevant classes: Category_Interface and Category_File_Manager

The purpose of this project is that it can be referenced from other projects. It handles the underlying file system automatically when creating/accessing categories.

To do that, class Category_Interface accesses class Category_File_Manager . Functions in Category_File_Manager are public for this reason.

If I reference Category_Helper_Project from another Project, is it possible to make Category_File_Manager inaccessible from the other project whilst keeping it accessible from Category_Interface? Accessing Category_Interface? Accessing Category_File_Manager` directly most likely causes problems in the tree structure.

Lastly I would like to know if making Category_File_Manager inaccessible will also make it inaccessible in unit tests, which would be quite unfortunate.

I have found some simmilar questions such as Making a function only accessible from one other function but they didnt really answer my questions.

Answer 1

To control class accessibility you have a keyword you add before its declaration:

public class Category_File_Manager 

If you do not add the public it defaults to internal and that would result in class being accessible from project/library that declares it and not accessible from any other, that includes tests.

You can circumvent this using InternalsVisibleTo assembly level attribute for test library benefit.

[assembly: InternalsVisibleToAttribute("Category_Helper_Project_Tests")]

This has a bit of a code smell that your library becomes somewhat aware of the test library but this is a case of having a cake and eating it. It is a good idea to remove such access from production code so I would wrap this in compilation if so it is not added on release build.

#if DEBUG
[assembly: InternalsVisibleToAttribute("Category_Helper_Project_Tests")]
#endif

Answer 2

as i have read your question over and over I reckon that you want to hide a class to other projects and also make it accessible from the inside of Category_File_Manager this cannot be done with one access modifier you should simply make Category_Interface internal to hide it from outside and make another class with only needed APIs to pass out from inside of Category_File_Manager More You can read here about access modifiers