CODEWITHSUNDEEP
c#asp.net-mvcentity-frameworkasp.net-mvc-4selection
user2678968
user2678968

Reputation: 5

ASP.NET MVC4 @Html.ListBoxFor Multiple to DB using EF

Hi I am still new to MVC4, I would like to use HTML helper to create a select box that would allow users to select multiple items using CTRL Click and store results using EF. Here is my view

@model AtomicQuestionnaire.Models.Questionnaire

@{
    ViewBag.Title = "Create";
}

@{
    var ListInterest = new List<SelectListItem>()
{
new SelectListItem(){Value="Stamp Collecting",Text="Stamp Collecting"},
new SelectListItem(){Value="Listening to Music",Text="Listening to Music"},
new SelectListItem(){Value="Reading",Text="Reading"}
};




}

<h2>Create</h2>



@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

        <div class="editor-label">
            @Html.LabelFor(model => model.Interest)
        </div>
        <div class="editor-field">
            @Html.ListBoxFor(model => model.Interest, ListInterest, new { size = "15", Multiple = "multiple" })
            @Html.ValidationMessageFor(model => model.Interest)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

And here is my model

public class Questionnaire
{
    public int ID { get; set; }
    public string Name { get; set; }
    public string City { get; set; }
    public string VisitorDesc { get; set; }
    public string Interest { get; set; }
    public int SiteRating { get; set; }
}

and my controller for create action

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(Questionnaire questionnaire)
{
    if (ModelState.IsValid)
    {
        db.Questionnaires.Add(questionnaire);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    return View(questionnaire);
}

I was only able to store the first item of the html selection box to database. Would you be able to tell me what I did wrong? I would like to store all selected items into DB. Thanks

Upvotes: 0

Views: 4858

Answers (1)

nativehr
nativehr

Reputation: 222

Since you want to select multiple listbox values you have to define your model's property as

public virtual ICollection<Interest> Interests { get; set; },

not as

public string Interest { get; set; }

If Interests property is collection, you will need a separate table to store them (separate entity at the EF level).

public class Interest
{
    public int ID { get; set; }
    public string Title { get; set; }
    public virtual ICollection<Questionnaire> Questionnaires { get; set; }
}

For there entities EF will generate Interests table and a junction table to store Questionnaire-Interest associations.

The view:

@{
    var ListInterest = new List<SelectListItem>() //hard-code, better load interests from db
{
new SelectListItem(){ Value = 1, Text="Stamp Collecting" },
new SelectListItem(){ Value=2, Text="Listening to Music" },
new SelectListItem(){ Value=3, Text="Reading"}
}; 

Html.ListBoxFor(c => c.Interests,
                new MultiSelectList(ListInteres, "Value", "Text"))

Notice, that Interest Entities must exist in db (or SaveChanges will raise an exception). You can add them manually for now or write a separate add/edit page.

Upvotes: 1

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