i hvae this editor for in mvc, i want to add static checkbox on above of it and when checkbox is checkbox the value of editfor is "NA" and when uncheck checkbox so editfor value is blank

Code: 

<div class="form-group">
    @Html.LabelFor(model => model.heading, htmlAttributes: new { @class = "control-label
    col-md-2" })
    <div class="col-md-10">
        @Html.EditorFor(model => model.heading, new { htmlAttributes = new { @class = "form-control"
        } }) @Html.ValidationMessageFor(model => model.heading, "", new { @class = "text-danger"
        })
    </div>
</div>