Question

all…

I’m using RavenDB embedded, latest stable build using NuGet and MVC 3.

    public JsonResult GetStudents(GridFilter filter)
    {
        using (var session = _store.OpenSession())
        {
            var students = session.Query<Student>();
            students.OrderBy(x => x.FirstName);

            return Json(students.ToList());
        }
    }

This code doesn’t break. It also doesn’t sort on Student.FirstName. I looked at the RavenQueryInspector (mousing over the students collection) and found the following…

AsyncDatabaseCommands = '(((Raven.Client.Linq.RavenQueryInspector<UMA.KendoGrid.Entities.Student>)(students))).AsyncDatabaseCommands' threw an exception of type 'System.NotSupportedException'

If I do

var students = from x in session.Query<Student>()
        orderby x.FirstName descending
        select x;

that works fine. First, I don’t understand why using lambda fails when using the long linq syntax works. What I REALLY need is to filter students by any field, as I’m using a grid with sort ability. I would like to use the System.Linq.Dynamic file from Microsoft to sort by string name, that way I can sort by whatever fields are passed in my sort collection.

But, to get started, I think I need to figure out why my version of RavenDB embedded won’t allow me to use lambda expressions. Can anyone help?

Answer 1

On this statement:

students.OrderBy(x => x.FirstName);

… you’re ignoring the result of the call. It’s the LINQ equivalent of the “ignoring the result of a string call” bug:

text.Substring(5, 10);

LINQ calls never change what they’re called on – they return a new collection with the appropriate transformation. So you want:

students = students.OrderBy(x => x.FirstName);

Or, better:

var students = session.Query<Student>.OrderBy(x => x.FirstName);