Asp.Net MVC4 Display CheckboxList

Question

I have searched a lot and spend 3 days only for searching and trying different technique (on stackoverflow etc) but I find no solution for implementing checkboxlist in asp.net mvc. And at last I am posting my problem to stackoverflow;
So, my model looks like this;

Many to Many relationship of my model(1 category may contain many projects and a project may belongs to many categories)
My controller;

 [HttpGet]
    [Authorize(Roles = "Admin")]
    public ActionResult ProjectAdd()
    {
        return View();
    }

My view;

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

    <fieldset>
        <legend>Add New Project</legend>

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

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

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

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

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

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

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

        <p>
            <input type="submit" value="Create" class="submit" />
        </p>

So, my question is How do I display checkboxlist for categories in my view?
How do I get selected values from that checkboxlist?

Answer 1

You need to have an object that will have a list of all categories , for example, you could do this:

[HttpGet]
[Authorize(Roles = "Admin")]
public ActionResult ProjectAdd()
{
    // Get all categories and pass it into the View
    ViewBag.Categories = db.ListAllCategories();

    return View();
}

in the top of your View

@model Database.Project
@{
   // retrieve the list of Categories
   List<Database.Category> categories = ViewBag.Categories;
}

and then replace this

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

for this

    <div class="editor-label">
        <label for="categories">Categories</label>
    </div>
    <div class="editor-field">
        @foreach(var c in categories) {

        <label class="checkbox">
            <input type="checkbox" name="categories" value="@c.CategoryId"> @c.CategoryName
        </label>

        }
    </div>

back in your Controller

[HttpPost]
[Authorize(Roles = "Admin")]
public ActionResult ProjectAdd(Database.Project model, int[] categories)
{
    if(ModelState.IsValid) {

        // fill up categories
        db.InsertAndSaveProject(model, categories);

    }

    ...

    return redirectToView("ProjectAdd");
}

Answer 2

Answer suggested by @balexandre above works great. However, I used following HTML Extension for CheckBoxList.

1. CheckboxList in ASP.net MVC4
2. Source Code:HTML Extension Helper method (Github)

The Major advantage of using this helper method is clean code and better readability. Eg

@Html.CheckBoxListFor(model => model.SelectedItems, Model.AllItems)