Properties private set;

Question

I know it only allows the class to set it, but what is the point?

How do I solve the problem of having readonly ids?

Say I have a person class:

public class Person     {         public string Name { get;  set; }         public int Id { get; private set; }         public int Age { get; set; }     } 

And this is in an Entities.dll, used by a GUI, BL and DAL.

The GUI calls the BL:

   List<Person> p =  BL.PeopleBL.GetPeople(); 

For the sake of the example calls the DAL:

... while(dr.read()) {     returnPersonList.add( new Person{ Age=dr.GetInt32(1), Id=dr.GetInt32(0), Name=dr.GetString(2)}) } ... 

of course I cannot do that cause Id is a private set; What is the proper way to do this?

How can I let the BL/Dal set the Id, but not on the GUI?

Or is this not even the proper use of a private set?

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I just wanted to add that this is your typical DB app, where the pk is the Id and should not be changed( only by the BL/DAL)

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Answer 1

This is one possible solution although not very clean:

1. Make the property you need to expose to BAL & DAL internal
2. Mark BAL.dll & DAL.dll Internal Visible in assemblyinfo.cs

public class Person {     public Person(int id)     {          this.Id=id;     }      public string Name { get;  set; }     public int Id { get; internal set; }     public int Age { get; set; } } 

AssemblyInfo.cs for Entities.dll

[assembly: InternalsVisibleTo("DAL"), InternalsVisibleTo("BAL")] 

That way all your internals will be visible to DAL & BAL. This may not be desirable but I'm just suggesting one possible solution.

Answer 2

The two common approaches are either that the class should have a constructor for the DAL to use, or the DAL should use reflection to hydrate objects.