Store multi-type OrderBy expression as a property

Question

In a generic abstract base class I\'m storing a couple of expressions used for ordering:

public Expression> OrderByString { get;          


        

Answer 1

Amy B's answer is great, and I based my own solution on it. So my point is more of an improvement for what I needed, which I am likely to improve upon in time.

public interface IOrderer
{
    IOrderedQueryable Apply(IQueryable source);
}

public class OrderBy : IOrderer
{
    private Expression> _orderExpr;
    public OrderBy(Expression> orderExpr)
    {
        _orderExpr = orderExpr;
    }

    public IOrderedQueryable Apply(IQueryable source)
    {
        return source.OrderBy(_orderExpr);
    }
}   

public class ThenBy : IOrderer
{
    private Expression> _orderExpr;
    public ThenBy(Expression> orderExpr)
    {
        _orderExpr = orderExpr;
    }

    public IOrderedQueryable Apply(IQueryable source)
    {
        return ((IOrderedQueryable)source).ThenBy(_orderExpr);
    }
}   

public class OrderCoordinator
{
    public List> Orders { get; private set; } = new List>();

    public IQueryable ApplyOrder(IQueryable source)
    {
        foreach (IOrderer orderer in Orders)
        {
            source = orderer.Apply(source);
        }
        return source;
    }

    public OrderCoordinator OrderBy(Expression> orderByExpression)
    {
        Orders.Add(new OrderBy(orderByExpression));
        return this;
    }

    // Can add more sort calls over time
    public OrderCoordinator ThenBy(Expression> orderByExpression)
    {
        Orders.Add(new ThenBy(orderByExpression));
        return this;
    }
}   

Specify Coordinator with type:

public OrderCoordinator OrderCoordinator { get; private set; } = new OrderCoordinator();

Specify sort ordering:

OrderCoordinator.OrderBy(e => e.MyStringProperty).ThenBy(e => e.MyIntProperty);

Apply the ordering:

ordered = OrderCoordinator.ApplyOrder(ordered);