Is there any reason why my variable is always null? in my MVC project

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Hi all,

I have got method like this in my controller ...

in my controller i am receiving an id and and engine values as parameters and thn i am using these to filter the data. For some reason the turbo variable is always null even tho there is data in my database. I'm not sure to why this is .. could i possibly be missing anything?:?

C#

public ActionResult Vehicle( int? id, decimal? engine)
        {



            var turbo =
                _catalogue.Data.Where(x => x.manufacturerId == id && x.EngineLitreCapacity == engine)
                    .Select(x => x.Turbo).FirstOrDefault();
                



            var model =
                _catalogue.Data.FirstOrDefault(x => x.Turbo == turbo);
           
            return PartialView("_Vehicle", model);

          

    
        }

Thank you

Posted 6-Nov-15 3:21am

1Future

Updated 6-Nov-15 3:25am

v3

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Dave Kreskowiak · Answer 1 · 2015-11-06T04:09:00

FIRST, yes, THIS ONE IS FIRST...

Put a breakpoint on the first line in that method. Then run the code. Your code will stop on the breakpoint. Click in the Visual Studio window and hover the mouse on top of the variable names id and engine. It'll tell you what the values of those variables are. Make sure those values are what you expect. If not, you're digging around for a cause in the wrong place.

If those values ARE what you expect, then your WHERE clause in the LINQ query doesn't do what you think it does.

Richard Deeming · Answer 2 · 2015-11-06T03:40:00

Solution 1

If _turbo is null, that means there is no record in the table where both the manufacturerId is equal to the id parameter and the EngineLitreCapacity is equal to the engine parameter.

Posted 6-Nov-15 3:40am

Richard Deeming

Krunal Rohit · Answer 3 · 2015-11-06T03:48:00

Solution 2

First convert your LINQ query to SQL and run it from SSMS, see if you can actually get the data for the given conditions. Or do the vice-versa.

This way you can double check your result.

-KR

Posted 6-Nov-15 3:48am

Krunal Rohit

Comments

Dave Kreskowiak 6-Nov-15 10:10am

Not first. First thing is to make absolutely sure the values coming into the method are what is expected. If they are correct THEN you can go spelunking around the query and the database.