blog.cs

public interface IQueries
{
  Foo GetFoo(int fooId);
  IEnumerable<Foo> QueryFooByBar(int barId);
}

public interface ICommands
{
  void AddFooToBar(int barId, Foo foo);
}

public class Repository : IQueries, ICommands
{
  public IQueries Queries { get { return this; } }
  public ICommands Commands { get { return this; } }
  
  Foo IQueries.GetFoo(int fooId) {
    // Implementation
  }
  
  // Other interface implementations
}

// Some other code
{
  var repository = new Repository();
  var foo = repository.Queries.GetFoo(1);
  repository.Commands.AddFooTobar(2, foo);
}