Check box that returns two values


I am currently using javascript to generate HTML for checkboxes however when I go to post the form to my controller which accepts FormCollection as a parameter.

I then put these values into a dictionary and inspect the value within my dictionary. While other checkboxes only return one value, my autoDiscovery checkbox returns two which are 'on' and 'true', which doesn't make sense to me.

Here is the rendered HTML

<div class="form-group">
    <div class="col-md-10">
        <label class="col-md-3 control-label" for="autoDiscovery">
            <input id="autoDiscovery" type="checkbox" checked="" data-val="false" name="autoDiscovery">
            <input type="hidden" name="autoDiscovery" value="true"> Auto Discovery

and here is the javascript I am using to assign the checkboxes

function AssignCheckbox(variableName, jsonData, caption) {
var checked = jsonData == 1 ? 'checked' : '';
var value = jsonData == 1 ? 'true' : 'false';
    return divFormGroupOpening + divOpeningInput +
            '<label class="col-md-3 control-label" for="' + variableName + '">' + '<input id="' + variableName + '" type="checkbox" name="' + variableName + '"  data-val="false"' + checked + '>' +
            '<input type="hidden" value="' + value + '" name="' + variableName + '">' +
            ' ' +  caption +'</label></div></div>';

Inspect the html generated when you use the @Html.CheckBoxFor() method. It generates

<input type="checkbox" name="autoDiscovery" value="true" ..... />
<input type="hidden" name="autoDiscovery" value="false" />

You need to mimic that. Currently your checkbox element does not have a value attribute so if its checked in the view it will post back "on". And your hidden input value is "true" so that value posts as well.

Just as important, do not use FormCollection. Post back to a model, or add a parameter in the method - bool autoDiscovery so the DefaultModelBinder will correctly set the value to either true or false depending on the checked state of the checkbox