public interface IFoo

{

    int SomeInt { get; set; }

}

​

public struct Foo : IFoo

{

    int IFoo.SomeInt { get; set; }

    public void DoSomething()

    {

        // Can't do this line

        //SomeInt = 42;

        (this as IFoo).SomeInt = 42;

    }

}

​

public class Program

{

    public static void Main()

    {

        Foo f = new Foo();

        f.DoSomething();

        System.Console.WriteLine($"{(f as IFoo).SomeInt}");

    }

}