Sorting incoming data

March 16, 2023

I have the controller that sends me data from the database. Currently I am using switch() statement to do sorting logic and my code looks like this

switch (sort)
{
    case "title":
        books = books.OrderBy(b => b.Title);
        break;
    case "novelti_asc":
        books = books.OrderBy(b => b.Date);
        break;
    case "novelti_des":
        books = books.OrderByDescending(b => b.Date);
        break;
    default:
        books = books.OrderBy(b => b.Title);
        break;
}

This feels to me like an unnecessary code nesting. So I would like to know what is optimal solution for implementing data sorting.

>Solution :

I would use a Dictionary<string, Func<IQueryable<Book>, IQueryable<Book>>> like this:

var orderBy = new Dictionary<string, Func<IQueryable<Book>, IQueryable<Book>>>()
{
    { "title", bs => bs.OrderBy(b => b.Title) },
    { "novelti_asc", bs => bs.OrderBy(b => b.Date) },
    { "novelti_des", bs => bs.OrderByDescending(b => b.Date) },
};

And then write:

books = orderBy[orderBy.ContainsKey(sort) ? sort : "title"](books);

The advantage here is that you can extend the functionality at run-time. You simply add more elements to the dictionary. You perhaps might give different users different options.