internal member in an interface

public interface IAM
	{
		int ID { get; set; }
		void Save();
	}

	public class concreteIAM : IAM
	{
		 public int ID{get;set;}
		 internal void Save(){
		 //save the object
		 }

		//other staff for this particular class
	}

	public class MyList : List<IAM>
	{
		public void Save()
		{
			foreach (IAM iam in this)
			{
				iam.Save();
			}
		}

		//other staff for this particular class
	}

internal void Save(){

public abstract class AM
{
    public int ID { get; set; }
    internal abstract void Save();
}

public class concreteIAM : AM
{
    internal override void Save()
    {
        //Do some save stuff
    }
}

public class AMList : List<AM>
{
    public void SaveItems()
    {
        foreach (var item in this)
        {
            item.Save();
        }
    }
}

internal interface InternalIAM
{
    void Save();
}

public class concreteIAM : InternalIAM
{
    void InternalIAM.Save()
    {
    }
}

internal interface IAMSaver { void Save(IAM item); }

internal class AMSaverFactory {
  IAMSaver GetSaver(Type itemType) { ... }
}

public class MyList : List<IAM>
{
  public void Save()
  {
    foreach (IAM itemin this)
    {
      IAMSaver saver = SaverFactory.GetSaver(item.GetType());
      saver.Save(item)
    }
  }
}

internal interface IPersist
    {
        void Save();
    }
    public class Concrete : IPersist
    {
        void IPersist.Save()
        {
            Console.WriteLine("Yeah!");
        }
    }

// Mylist.cs in the same assembly can still call save like
public void SaveItems()
    {
        foreach (IPersist item in this)
        {
            item.Save();
        }
    }

new Concrete().Save();     // doesn't compile. 'Concrete' does not contain a definition for 'Save'

public interface IAM
{
        int ID { get; set; }
}


internal interface IAMSavable
{
        void Save();
}

public class concreteIAM : IAM, IAMSavable
{
         public int ID{get;set;}
         public void IAMSavable.Save(){
         //save the object
         }

        //other staff for this particular class
}

public class MyList : List<IAM>
{
        public void Save()
        {
                foreach (IAM iam in this)
                {
                        ((IAMSavable)iam).Save();
                }
        }

        //other staff for this particular class
}

public abstract class Item
{
    public int ID { get; set; }
    protected abstract void Save();

    public class ItemCollection : List<Item>
    {
        public void Save()
        {
            foreach (Item item in this) item.Save();
        }
    }
}

public sealed class NiceItem : Item
{
    protected override void Save()
    {
        // do something
    }
}

using System;

public interface IPublic
{
    void Public();
}

internal interface IInternal : IPublic
{
    void Internal();
}

public class Concrete : IInternal
{
    public void Internal() { }

    public void Public() { }
}

public interface IAM
{
    int ID { get; set; }
}
internal interface IAMSave
{
    void Save();
}

public class concreteIAM : IAM, IAMSave
{
    public int ID { get; set; }
    internal void Save()
    {
        //save the object
    }
    //other staff for this particular class
}

public class MyList : List<IAM>
{
	public void Save() {
		foreach (IAM iam in this) {
			((IAMSave)iam).Save();
		}
	}
	//other staff for this particular class
}