MVC Binding to checkbox

Question

I have found so many questions about this, but none of them go over or seem to go over my scenario. I have a model:

public class CheckBoxModel
{
                     


        

Answer 1

An alternative to Darin's fantastic answer

I definitely recommend following Darin's approach for returning classes which will be most of the time. This alternative is a 'quick' and dirty hack if all you need is the checked Ids:

<% foreach (var cb in Model.CheckBoxes) { %>
  <div>
    <input type="checkbox" 
      value="<%= cb.Id %>"
      <%= cb.IsSelected ? "checked=\"checked\"" : "" %>
      name="ids" />
  </div>
<% } %>

Will bind to the int[] ids parameter in the following action:

[HttpPost]
public ActionResult MyAction(int[] ids) 
{
    // ids contains only those ids that were selected
    ...
}

• The benefit is cleaner html as there is no hidden input.
• The cost is writing more code in the view.

In MVC 4.0 (Razor 2.0) you can use the following syntax in your view:

<input type="checkbox" value="@cb.Id" checked="@cb.IsSelected" name="ids" />

Answer 2

Try like this:

<%= Html.CheckBoxFor(x => x.IsSelected) %>

Also if you want to pass along the id don't forget to do so:

<%= Html.HiddenFor(x => x.Id) %>

And if you had a collection of those:

public class MyViewModel
{
    public CheckBoxModel[] CheckBoxes { get; set; }
}

you could:

<% for (var i = 0; i < Model.CheckBoxes.Length; i++) { %>
    <div>
        <%= Html.HiddenFor(x => x.CheckBoxes[i].Id) %>
        <%= Html.CheckBoxFor(x => x.CheckBoxes[i].IsSelected) %>
    </div>
<% } %>

which will successfully bind to:

[HttpPost]
public ActionResult MyAction(MyViewModel model) 
{
    // model.CheckBoxes will contain everything you need here
    ...
}