ASP.NET MVC dropdown-list from database

Question

Ok, so I\'m new to this whole MVC-world, but it seems to be a pretty good way of getting things done and I\'m trying to make it work here.

The problem is: I can\'t g

Answer 1

this is my table in the database

take look it my Action controller

    // GET: Letters
    public ActionResult Index()
    {
        ViewBag.LetterStatus = new SelectList(LetterStatusService.GetAllLettersStatus(), "Id", (CultureHelper.GetCurrentCulture() == "ar") ? "NameArabic" : "Name", Request.QueryString["LetterStatus"]);
        return View();
    }

and in the view

  @Html.DropDownList("LetterStatus")

the constructor I used is

new SelectList(
    list<Objlect> myListFromDatabase,
    string PropertyNameOfValueInHtml,
    string PropertyNameOfDesplayInHtml,
    string SelectedItemValue 
);

this line Request.QueryString["LetterStatus"] because I send the Selected Items within QuerySrting

and based on CurrentCulture I chose what column to display

and the result are

but I think the best way to do this,,,, is to get or create the Items then Iterate throw them to generate the select tag manually. I described this approach well in this answer

hope this helps you

Answer 2

Add the SelectList to your model:

public SelectList DropDownList { get; set; }

build the class for that collection:

public class MyListTable
{
    public string Key { get; set; }
    public string Display { get; set; }
}

and then in your controller, load the data for the MyListTable class from the database:

var list = new List<MyListTable>();

using (SqlConnection c = new SqlConnection(cString))
using (SqlCommand cmd = new SqlCommand("SELECT KeyField, DisplayField FROM Table", c))
{
    using (SqlDataReader rdr = cmd.ExecuteReader())
    {
        while (rdr.Read())
        {
            list.Add(new MyListTable
            {
                Key = rdr.GetString(0),
                Display = rdr.GetString(1)
            });
        }
    }
}

var model = new users();
model.DropDownList = new SelectList(list, "Key", "Display");

and then finally, you need to send your model to the view:

return View(model);

Now in the Razor you can display this:

@Html.DropDownListFor(m => Model.DropDownList);

You of course can name these things better names, but you get the idea.

Answer 3

I find this system works (and avoids using ViewBag):

View Model:

public class YourViewModel
{
    // This could be string, int or Guid depending on what you need as the value
    public int YourDropdownSelectedValue { get; set; }
    public IEnumerable<SelectListItem> YourDropdownList { get; set; }
}

Controller:

// Get database values (by whatever selection method is appropriate)
var dbValues = db.YourEntity.ToList();

// Make Selectlist, which is IEnumerable<SelectListItem>
var yourDropdownList = new SelectList(dbValues.Select(item => new SelectListItem
{
    Text = item.YourSelectedDbText,
    Value = item.YourSelectedDbValue
}).ToList(), "Value", "Text");

// Assign the Selectlist to the View Model   
var viewModel = new YourViewModel(){
    // Optional: if you want a pre-selected value - remove this for no pre-selected value
    YourDropdownSelectedValue = dbValues.FirstOrDefault(),
    // The Dropdownlist values
    YourDropdownList = yourDropdownList
};

// return View with View Model
return View(viewModel);

and in the View:

@Html.DropDownListFor(a => a.YourDropdownSelectedValue, Model.YourDropdownList, "select this text - change this to null to exclude", new { @class = "your-class" })

Answer 4

If you are really new to ASP.Net MVC, this is a quite good Tutorial that shows you how the MVC-Pattern works.

MVC3: http://www.asp.net/mvc/tutorials/getting-started-with-aspnet-mvc3/cs/intro-to-aspnet-mvc-3
MVC4: http://www.asp.net/mvc/tutorials/mvc-4/getting-started-with-aspnet-mvc4/intro-to-aspnet-mvc-4

Here is the sample-code to download: http://code.msdn.microsoft.com/Introduction-to-MVC-3-10d1b098

this is an helpful video: http://www.asp.net/mvc/videos/mvc-1/conference-presentations/creating-nerddinnercom-with-microsoft-aspnet-model-view-controller-mvc

Answer 5

There a great answers already but Here is another approach.

You will use user as a model, ListUserViewModel as view-model and UserController as the contoller. The work of view-model is to carry all info needed to be displayed on the page from the controller without adding unwanted properties into the model class. In your case list of users from database into the drop down list.

Model:

public class User     //By the way use singular when naming a class
{
    public string name {get; set;}
    public int user_id {get; set;}
}

View-model

public class ListUserViewModel
{
    public list<User> Users{get; set;}
}

Controller

public class UserController : Controller
{
    private DataBaseContext db = new DataBaseContext();

    [HttpGet]
    public ActionResult ListUser()
    {
        var users = db.Users.ToList();

        var viewModel = new ListUserViewModel { Users = users };

        return View(viewModel);
    }
}

Now use ListUserViewModel instead of User in your view as a model

@model Community.Models.ListUserViewModel

and the drop down

@Html.DropDownListFor(m => m.Users, new SelectList(Model.Users, "user_id", "name"), " ")

Explanation:

You are creating drop down list for Users with Model.Users as select list data source. "user_id" as a value of the selected user and "name" as display label. the last argument( i put empty string " ") is a default value that the drop down will display before selection.

I hope this will help you or someone else.

Answer 6

Try this,

model

public string CoutryID { get; set; }
public List<SelectListItem> CountryList { get; set; }

Controller method which fill the list

public List<Country> getCountryList()
        {
            using (QRMG_VendorPortalDataContext _context = new QRMG_VendorPortalDataContext())
            {
                return (from c in _context.Countries
                        where c.IsDeleted == false
                        select c).ToList();
            }
        }

Drop down list in View

 @Html.DropDownListFor(m => m.CoutryID,
         new SelectList(Model.CountryList,
                        "CoutryID", "Value"))