ASP.NET MVC3: Applying a SELECT / WHERE Statement from MVC View

Question

I have list of items contained in viewbag ViewBag.RoomBookings

As an example:

I want all the Roombookings with ViewBag.RoomBookings.RoomNo = 6 AND ViewBag.RoomBookings.Time < DateTime.Now AND ViewBag.RoomBookings.Time < DateTime.Now + 3600

Looping through is a NO.

And it must be done on the view, as I also need access to all the other roombookings too to populate a timetable.

Alternatively, Im thinking of Hash lists? Where I could list it with RoomNo, and Time and access it that way. But I cant find any good documentation on this if its even possible.

Ive tried a few things (just to test a method that works (these wont follow the same critera as above)):

      var RoomBookingsTemp = ViewBag.RoomBookings;

      var newlist = (from RoomOcc in RoomBookingsTemp where RoomOcc.EndDateTime < DateTime.Now select RoomOcc.RoomNo);
      var bookings = RoomBookingsTemp.Where(roombooking => DateCheckStart < roombooking.EndDateTime && DateCheckEnd > roombooking.StartDateTime && roombooking.RoomNo == RoomNo);
      var newlist = RoomBookingsTemp.Select(m => m["RentalNo"]);

But none are valid.

i would think the linq approach you have suggested would do what you are trying to do. can you state what it is that makes you say it's not valid? — Dave Rael
– Dave Rael, Commented Nov 24, 2011 at 14:03
if linq is the first one, "Query expressions over source type 'dynamic' are not allowed". Other 2 give "Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type " — IAmGroot
– IAmGroot, Commented Nov 24, 2011 at 14:35
Quoting some worrying phrases from your question: I have list of items contained in viewbag and And it must be done on the view. Using ViewData/ViewBag, and writing complex code in the view which would otherwise belong to a view model are two very bad practices for me. — Darin Dimitrov
– Darin Dimitrov, Commented Nov 24, 2011 at 15:02
The view is for presentation and shouldn't contain logic. Create the structure you need in the controller and display it in the view — Jason
– Jason, Commented Nov 24, 2011 at 15:07

BZink · Accepted Answer · 2011-11-24 15:00:00Z

2

You need to cast the RoomBookingsTemp variable. When you declare it directly from the ViewBag it's still a dynamic type [details about viewbag] and the error your seeing is that linq can't query/iterate over a dynamic type.

I'm not sure what type you're actually using but try something like this...

var RoomBookingsTemp = ViewBag.RoomBookings as List<RoomBooking>;

or

List<RoomBooking> RoomBookingsTemp = ViewBag.RoomBookings;

answered Nov 24, 2011 at 15:00

BZink

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1 Comment

IAmGroot Over a year ago

scratches head I swear I tried this. On second thoughts,maybe I left out the fact its a list of custom objects. Cheers!

James Hull · Accepted Answer · 2011-11-24 14:02:42Z

0

What's wrong with your second method? You are just missing the select.

// Some statements removed from where for clarity
var bookings = RoomBookingsTemp.Where(rb => rb.RoomNo == 6).Select(rb => rb);

answered Nov 24, 2011 at 14:02

James Hull

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4 Comments

IAmGroot Over a year ago

"Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type "

BZink Over a year ago

Can you show the code where you declare RoomBookingsTemp from the ViewBag.

IAmGroot Over a year ago

var RoomBookingsTemp = ViewBag.RoomBookings

James Hull Over a year ago

It's because ViewBag is dynamic. Either use a statically typed view model (which I highly recommend) or try: List<RoomBookings> RoomBookingsTemp = ViewBag.RoomBookings; // Assuming ViewBag.RoomBookings is a List of RoomBookings

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