Question

I have a winform application made up of two assemblies : a business layer and a front-end layer. Each usercontrol (front-end layer) relates to a class of the business layer, i.e. CustomerUserControl uses the Customer class.

Editable properties, i.e. Customer.Name, have public setters so that their values can be modified through front-end controls.

My question is : is it possible to change the setter accessibility of a property to make it more or less restrictive only for specific classes. In my example, the Customer.Name setter would be internal, that is not accessible by front-end controls but accessible for its corresponding control CustomerUserControl. Or else, the setter would be public but not accessible to controls other than CustomerUserControl.

Is it possible to achieve such customized access rights ?

Answer 1

I would use the internal modifier for the setter. This makes it only accessible inside the assembly. If the CustomerUserControl is in another assembly then you can use the InternalsVisibleToAttribute

[assembly: InternalsVisibleTo("assembly name")] 

EDIT: You are right. Here is another possibility:
Declare an interface that would be implemented by controls that are allowed to set names:

public interface ICustomerNameProvider
{
    string CustomerName { get; }
}

In Customer add a method:

public void SetName(ICustomerNameProvider customerNameProvider)
{
    this.Name = customerNameProvider.CustomerName;
}

The CustomerUserControl would call it like this:

cust.SetName(this);

Of cause this is not absolutely fool proof, but accidentally passing the wrong control would become impossible.