CODEWITHSUNDEEP
c#asp.netasp.net-mvclinq
Louise
Louise

Reputation: 157

ASP.NET MVC concatenate names and map to ID#

I have a table which stores Person. The attributes are FirstName, LastName and PersonID. I have added the attribute

public string NameFull { get { return FirstName + " " + LastName; } }

and I am able to display the output as a concatenated name.

However, when the user makes the selection of the name, I want to store it as the PersonID.

Currently, I have this as my linq Where statement:

var personID= db.Persons
         .Where(h => Names == model.Person.NameFull)
         .Select(h => h.PersonID);
var idToSave = personID.AsEnumerable().FirstOrDefault().Trim().ToString();

In the controller:

SelectList names = new SelectList(db.Person.ToArray(), "PersonID", "NameFull");
ViewBag.Names = names;

Would anyone be able to point me in the right direction?

Upvotes: 1

Views: 3127

Answers (2)

Shaun Luttin
Shaun Luttin

Reputation: 141712

Running Fiddle

Here is a running fiddle that I created for you. Select a person and click submit. The selected person's id will display after the HTTP post.

Model

MyViewModel contains a List of persons and a SelectedPersonID. It is this view model that we bind to DropDownListFor.

using System.Collections.Generic;

namespace HelloWorld
{
    public class MyViewModel
    {
        public int SelectedPersonID { get; set; }
        public List<Person> Persons { get; set; }
    }

    public class Person
    {
        public int PersonID  { get; set; }
        public string First { get; set; }
        public string Last { get; set; }

        public string NameFull
        {
            get {

                return First + " " + Last;
            }
        }
    }
}

View

We bind the DropDownListFor to MyViewModel. Specifically, the first parameter is the current SelectedPersonId, and the second parameter is a new SelectList that we create from our view model.

@model HelloWorld.MyViewModel
@{
    Layout = null;
}

<!DOCTYPE html>    
<html lang="en">
    <head></head>
    <body>

        @using (Html.BeginForm())
        {
            @Html.DropDownListFor(
                m => m.SelectedPersonID, 
                new SelectList(Model.Persons, "PersonID", "NameFull"))
            <button type="sumbit">Submit</button>
        }
        <span>Selected Person's ID is @Model.SelectedPersonID</span>

    </body>
</html>

Controller

On the post back to the controller, we can retrieve the SelectedPersonID.

using System.Web.Mvc;
using System.Collections.Generic;
using System.Linq;

namespace HelloWorld
{
    public class HomeController : Controller
    {
        public FakeDb fakeDb = new FakeDb();

        [HttpGet]
        public ActionResult Index()
        {
            var vm = new MyViewModel {
                SelectedPersonID = fakeDb.Persons.FirstOrDefault().PersonID,
                Persons = fakeDb.Persons
            };

            return View(vm);
        }

        [HttpPost]
        public ActionResult Index(MyViewModel vm)
        {
            // this is redundant 
            // but illustrates how to access the selected id  
            vm.SelectedPersonID = vm.SelectedPersonID;
            vm.Persons = fakeDb.Persons;

            return View(vm);
        }
    }
}

FakeDb

This is just for demo purposes.

public class FakeDb
{
    public List<Person> Persons
    {
        get
        {
            var persons = new List<Person>();
            for (var i = 0; i < 10; ++i)
            {
                persons.Add(new Person()
                {
                    First = "First" + i, 
                    Last = "Last" + i, 
                    PersonID = i
                });
            }

            return persons; 
        }
    }
}

Upvotes: 1

Brendan Vogt
Brendan Vogt

Reputation: 26048

If I understand you correctly then you want the first name and last name to be displayed in the dropdown and when a user selects a name combination, then the person's ID has to be used instead? If so, then the code below is based on my assumptions above.

I have created the necessary classes as what I would have done it. Please excuse if I have left something out, the code below is not tested.

Your Person class will look something like this:

public class Person
{
     public int Id { get; set; }

     public string FirstName { get; set; }

     public string LastName { get; set; }

     public string FullName
     {
          get
          {
               return FirstName + " " + LastName;
          }
     }
}

I haven't worked with Entity Framework in ages, not sure if it will complain about FullName not being a column name in the persons table.

Create a PersonViewModel class that you will pass into the view.

public class PersonViewModel
{
     public PersonViewModel()
     {
          Persons = new List<Person>();
     }

     public int PersonId { get; set; }

     public List<Person> Persons { get; set; }
}

In your controller you will have something like this:

public ActionResult Create()
{
     PersonViewModel model = new PersonViewModel();

     // Get a list of all the people
     // I can't remember how to use Entity Framework to get a list of all the people,
     // it's something like the code below
     model.Persons = db.Persons;

     return View(model);
}

Your post action method:

[HttpPost]
public ActionResult Create(PersonViewModel model)
{
     // Do whatever you need to do
}

In your view the code will look like this:

@Html.DropDownListFor(
     x => x.PersonId,
     new SelectList(Model.Persons, "Id", "FullName", Model.PersonId),
     "-- Select --"
)

The code above should display the first name and last name in the "text" part of the dropdown, and the ID of the person in the value of the dropdown.

I hope you come right :)

Upvotes: 2

Related Questions