MVC 3 - Scaffolding drop down list

Question

I am playing with the Scaffolding that is in Asp.net mvc

I have a property on my view model for countries

public IEnumerable<SelectListItem> Countries { get; set; }

Yet, when I create a view and specify the viewmodel it doesn't scaffold a drop down list as I expected it to. In fact it get completely ignored.

I have compiled the project before doing it

I also tried adding a property like this

public int CountryId { get; set; }

As this article suggested there is a convention at work

http://blog.stevensanderson.com/2011/01/28/mvcscaffolding-one-to-many-relationships/

I am using the Add view option you have when right clicking in a controller action method

Any ideas what is wrong?

score 5 · Answer 1 · answered Apr 17 '11 at 11:27

In my current project, i faced this problem and couldn't find a quick way to scaffold the Dropdown list of a one-many relation inside one of my Entities.

What I ended up doing was like the following:

1- Create the normal AddView=>Create way.

2- If i had a ID property in my model class, the defaul;t template will generate something like this to represent this property in my view:

<div class="editor-label">
                @Html.LabelFor(model => model.CityID)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.CityID)
                @Html.ValidationMessageFor(model => model.CityID)
</div>

3- Now I need to replace this default template with a working one, so I wrote this code in the CREATE method:

IEnumerable<SelectListItem> cityItems = dataContext.Cities.AsEnumerable().Select(c => new SelectListItem()
            {
                Text = c.Name,
                Value = c.ID.ToString(),
                Selected = false,
            });
            SelectList cityList = new SelectList(cityItems, "Value", "Text");
            ViewBag.CityList = cityList;

this will fetch the Cities table and create a Selectlist that i can pass to my view and work with it to provide the DrobDown with it's items.

4- replace the default code in my View by one like the following:

<div class="Post-label">
                        <div class="editor-label">
                            @Html.LabelFor(model => model.CityID)
                        </div>
                        <div class="editor-field">
                          @Html.DropDownListFor(m => m.CityID, ViewData["CityList"] as SelectList)
                            @Html.ValidationMessageFor(model => model.CityID)
                        </div>
</div>

The reason I've used ViewData["CityList"] instead of ViewBag.CityList is that this one worked but the other not.

5- now my view is working find and is fetching the City data just like what I expected, and using the same model inside my Edit view resulted in a working one too.

Give it a try and let me know what happened, Thanks.

thanks for the reply. I know how to hand code it, I'm just trying to find out why the automatic scaffolding doesn't work for this scenario — ChrisCa, Apr 17 '11 at 12:51

score 4 · Answer 2 · answered Sep 19 '12 at 16:24

I have noticed that for a given model, the "Create" scaffold-generated code when creating a new controller is different than if you right-click in an existing controller and say "Add View" and choose the "Create" scaffolding template. In the first case, given you have the correct properties on the child class

public Country Country {get;set;}
public int CountryID {get;set;}

then this case (adding controller with MVC scaffolding read/write and appropriate Model class) WILL generate a @Html.DropDownList for the parent relationship, whereas right-clicking within the controller Create method will not scaffold the drop-down but will instead create an @Html.EditorFor for the relationship.

So the answer if you want scaffolding code to generate the drop-down may be to delete and re-create your controller if possible, otherwise manually add in the appropriate code.

score 1 · Answer 3 · answered Aug 05 '11 at 21:33

In order to have the option to choose a country with a dropdown the property in your Model should be:

public Country Country{ get; set; } Navigation property used by EF, doesn't involve the database

with

public Country CountryId{ get; set; } Create the foreign key on the Person table

Each instance/record of a person is associated with a country: the relation is defined with the navigation property via code and with the CountryID for the database. The scaffholding template will then generate the edit/create methods and views using :

ViewBag.PossibleCountries

Here's a similar scenario.

MVC 3 - Scaffolding drop down list

3 Answers3