Get a single text value using linq

Question

I am using this line to return a value, but instead its getting a True

var valor = valoresCampoAdicionalesEmpresa.Select(p => p.Key == propiedad.Nombre).First();

This the view data passes from the controller

var valoresCampoAdicionalesEmpresa = (Dictionary)ViewData["ValoresCampoAdicionalesEmpresa"];

public ActionResult Edit(int? id)
        {
            var listFields = from b in db.Propiedades
                             where b.Entidad.Nombre == "Empresa"
                             select b;
            ViewData["CamposAdicionalesEmpresa"] = listFields.ToList<Propiedad>();

            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Empresa empresa = db.Empresas.Find(id);
            if (empresa.PropiedadesExtra != null)
            {
                XElement xmlTree = XElement.Parse(empresa.PropiedadesExtra);
                Dictionary<string, string> dict = new Dictionary<string, string>();
                foreach (var el in xmlTree.Elements())
                {
                    dict.Add(el.Name.LocalName, el.Value);
                }

                ViewData["ValoresCampoAdicionalesEmpresa"] = dict;
            }

            if (empresa == null)
            {
                return HttpNotFound();
            }
            return View(empresa);
        }

Dmitry · Accepted Answer · 2015-06-16 20:43:58Z

4

In that case, FirstOrDefault is what you want:

var valor = valoresCampoAdicionalesEmpresa.FirstOrDefault(p => p.Key == propiedad.Nombre);

edited Jun 16, 2015 at 20:43

Dmitry

14.1k6 gold badges38 silver badges53 bronze badges

answered Jun 16, 2015 at 20:38

Sébastien Cambon

493 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Justin Pihony · Accepted Answer · 2015-06-16 20:43:34Z

3

Change your Select to be a Where. Where uses a predicate to filter the data and return the same structure...just a subset. Select on the other hand changes the data structure to be whatever is evaluated in the provided function. In your case you are changing the structure to be a single Boolean result equivalent to whether Key equals Nombre. The fixed code is below:

var valor = valoresCampoAdicionalesEmpresa.Where(p => p.Key == propiedad.Nombre).First();

And, as pointed out in the comments, First* accepts a predicate itself, so you can simply call First as a combined Where and First

var valor = valoresCampoAdicionalesEmpresa.First(p => p.Key == propiedad.Nombre);

First will throw if there is nothing, so you can use FirstOrDefault if that fits better

edited Jun 16, 2015 at 20:43

answered Jun 16, 2015 at 20:29

Justin Pihony

67.2k20 gold badges154 silver badges185 bronze badges

2 Comments

Steve Over a year ago

Correct but First takes the same condition of Where

Justin Pihony Over a year ago

@Steve Agreed, amended!

aherocalledFrog · Accepted Answer · 2015-06-16 20:29:30Z

2

Needs to be .Where(), not .Select(). .Select() returns the result of the expression, which is a boolean. .Where() returns the result where the expression is true.

answered Jun 16, 2015 at 20:29

aherocalledFrog

8609 silver badges14 bronze badges

Comments

maraaaaaaaa · Accepted Answer · 2015-06-16 20:40:02Z

1

use .FirstOrDefault() and wouldnt hurt to be a bit more explicit in the declaring.

string? valor = valoresCampoAdicionalesEmpresa.FirstOrDefault(p => p.Key == propiedad.Nombre);

answered Jun 16, 2015 at 20:40

maraaaaaaaa

8,2013 gold badges25 silver badges42 bronze badges

Collectives™ on Stack Overflow

Get a single text value using linq

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related