Cannot implement property with protected set from interface

Question

I have an interface which has a property with public get and protected set.

Yet when I implement this in my class i get an error saying it must be public.

My interface looks like this:

public interface ISegment
{
    INode NodeA { get; protected set; }
    INode NodeB { get; protected set; }
    public sealed void SetNodeA(INode node) => NodeA = node;
    public sealed void SetNodeB(INode node) => NodeB = node;
}

My class Segment: ISegment has the properties declared like this:

[SerializeField]
protected Node _nodeA;
public INode NodeA
{
    get => _nodeA;
    protected set => _nodeA = value as Node;
}

[SerializeField]
protected Node _nodeB;
public INode NodeB
{
    get => _nodeB;
    protected set => _nodeB = value as Node;
}

And i get this error:

'Segment' does not implement interface member 'ISegment.NodeA.set'
'Segment' does not implement interface member 'ISegment.NodeB.set'

What am i misunderstanding here?

Answer 1

Do it like this

    public interface ISegment
    {
        INode NodeA { get; protected set; }
        INode NodeB { get; protected set; }
        public sealed void SetNodeA(INode node) => NodeA = node;
        public sealed void SetNodeB(INode node) => NodeB = node;
    }

    public class MyClass : ISegment
    {
        private Node _nodeA;
        private Node _nodeB;

        INode ISegment.NodeA
        {
            get => _nodeA;
            set => _nodeA = value as Node;
        }

        INode ISegment.NodeB
        {
            get => _nodeB;
            set => _nodeB = value as Node;
        }

        private void Do(INode node)
        {
            if(node == NodeA) { } // Error
            if(node == _nodeA) { } // Warning "Possibly unintended reference comparison"
            if (node == ((ISegment)this).NodeA) { } // OK
        }
    }

but the Question is, why do you want that? Why protected set ?

You can do it like this also. (Not helps here because of default implementation in the interface)

    public interface IFoo
    {
        public string Bar { get; }
    }

    public class Bubu : IFoo
    {
        public string Bar { get; protected set; }
    }

Update: Edited the code to show more exactly, how to access the properties