Pass LINQ anomyous type results like a collection of property bags to a ASP.NET 5 MVC View

Question

I've searched around and people talk about using ExpandDo with dynamic, but I haven't been able to figure it out how to do this with a collection returned from a LINQ query.

I'm doing an inner join on my database between 2 tables (student and enrollments)

    var innerJoin =
        from e in db.Enrollments
        join s in db.Student on e.StudentID equals s.StudentID
        select new { Student= s.Name , Course = e.CourseID };

I've tried

dynamic model = innerJoin.ToList().ToExpando();

return View(model)

and I have

@model System.Collections.Generic.IEnumerable<dynamic>

at the top of my View.cshtml

but that gives this error when I try navigating to the controller in the web application:

The model item passed into the dictionary is of type 'System.Dynamic.ExpandoObject', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[System.Object]'. ''

I also tried:

   dynamic model = innerJoin.ToList();

    return View(model);

but then in my view (.cshtml file) I

    @foreach (dynamic item in Model)
    {
        <tr>
            <td>
                @Html.Raw(item.Course)
            </td>
        </tr>
    }

it'll barf on the @Html.Raw line with

An exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in App_Web_index.cshtml.1bbec3a6.jtomobws.dll but was not handled in user code

Ideally I'd like to make it a one liner. In my view I'm hoping to be able to iterate over a collection of property bags, and extract the Student and Course fields. So my property bag would contain properties Student and Course, and they'd be a collection of them. I've looked at many similar posts, but none have done this

Thanks Thomas

Do not use `dynamic`! Create a view model with properties `Student` and `Course`. — , Feb 20 '16 at 07:46
Thanks, you're probably right, and I see that advice alot. Regardless, I'm interested in how to actually just get this working using dynamic, for learning's sake. — friartuck, Feb 20 '16 at 17:45

score 1 · Answer 1 · edited May 23 '17 at 11:50

EDITED

I assume that innerJoin.ToList().ToExpando(); converts the list of your anonymous objects returned from the join into Expando object and not to IEnumerable<dynamic>. If you want to get List of dynamic objects you can use something like:

var innerJoin = from e in db.Enrollments
                join s in db.Student on e.StudentID equals s.StudentID
                select e;


var model = new List<dynamic>();
foreach(var l in innerJoin)
{
    dynamic temp = new System.Dynamic.ExpandoObject();
    temp.Student = l.StudentID;
    temp.Course = l.CourseID;
    model.Add(temp);
}

This will work for System.Collections.Generic.IEnumerable<dynamic> model

Here is the example for working fiddle

Although I really advise you to use strongly typed models. By using dynamic objects you basically giving up on most of the advantages of statically typed languages.

Thanks alot, but now I'm getting Error CS0117 'ExpandoObject' does not contain a definition for 'Student' and the same for Course when I try to build — friartuck, Feb 20 '16 at 07:12

Pass LINQ anomyous type results like a collection of property bags to a ASP.NET 5 MVC View

1 Answers1