MVC3 EditorTemplate for a nullable boolean using RadioButtons

Question

I have a property on one of my objects that is a nullable boolean, I want my logic to have true represent Yes, false to be No and null to be N/A. Now because I am going to h

Answer 1

The problem is that you need to set the checked attribute because the Html.RadioButtonFor does not check a radio button based on a nullable bool (which appears to be a flaw).

Also by putting the radio buttons inside of the label tag, you can select value by clicking the label.

Shared/EditorTemplates/Boolean.cshtml

@model bool?
<label>
    <span>n/a</span>
    @Html.RadioButtonFor(x => x, "", !Model.HasValue ? new { @checked=true } : null) 
</label>
<label>
    <span>Yes</span>
    @Html.RadioButtonFor(x => x, true, Model.GetValueOrDefault() ? new { @checked = true } : null)
</label>
<label>
    <span>No</span>
    @Html.RadioButtonFor(x => x, false, Model.HasValue && !Model.Value ? new { @checked = true } : null)
</label>

Answer 2

You just need to handle the special null case like so:

<label class="radio">
  @Html.RadioButtonFor(x => x.DefaultBillable, "", new { @checked = !this.Model.DefaultBillable.HasValue })
  Not set
</label>
<label class="radio">
  @Html.RadioButtonFor(x => x.DefaultBillable, "false")
  Non-Billable
</label>
<label class="radio">
  @Html.RadioButtonFor(x => x.DefaultBillable, "true")
  Billable
</label>

Answer 3

@model bool?
<div data-ui="buttonset">
@{
    Dictionary<string, object> yesAttrs = new Dictionary<string, object>(); 
    Dictionary<string, object> noAttrs = new Dictionary<string, object>(); 
    Dictionary<string, object> nullAttrs = new Dictionary<string, object>(); 

    yesAttrs.Add("id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "Yes");
    noAttrs.Add("id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "No");
    nullAttrs.Add("id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "NA");

    if (Model.HasValue && Model.Value)
    {
        yesAttrs.Add("checked", "checked");
    }
    else if (Model.HasValue && !Model.Value)
    {
        noAttrs.Add("checked", "checked");
    }
    else
    {
        nullAttrs.Add("checked", "checked");
    }
}

@Html.RadioButtonFor(x => x, "true", yesAttrs) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))Yes">Yes</label>
@Html.RadioButtonFor(x => x, "false", noAttrs) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))No">No</label>
@Html.RadioButtonFor(x => x, "null", nullAttrs) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))NA">N/A</label>
</div>

Answer 4

How about some extension method fun to keep that "one line to rule them all". :-)

public static class DictionaryHelper
{
    // This returns the dictionary so that you can "fluently" add values
    public static IDictionary<TKey, TValue> AddIf<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, bool addIt, TKey key, TValue value)
    {
        if (addIt)
            dictionary.Add(key, value);
        return dictionary;
    }
}

And then in your template file you simply change the signature of how you are adding the additional parameters including the checked="checked" attribute to the element.

@model bool?
<div data-ui="buttonset">
@Html.RadioButtonFor(x => x, true, new Dictionary<string,object>()
    .AddIf(true, "id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "Yes")
    .AddIf(Model.HasValue && Model.Value, "checked", "checked")
) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))Yes">Yes</label>

@Html.RadioButtonFor(x => x, false, new Dictionary<string,object>()
    .AddIf(true, "id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "No")
    .AddIf(Model.HasValue && !Model.Value, "checked", "checked")
) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))No">No</label>

@Html.RadioButtonFor(x => x, "null", new Dictionary<string,object>()
    .AddIf(true, "id", ViewData.TemplateInfo.GetFullHtmlFieldId("") + "NA")
    .AddIf(!Model.HasValue, "checked", "checked")
) <label for="@(ViewData.TemplateInfo.GetFullHtmlFieldId(""))NA">N/A</label>
</div>

Answer 5

You can use a @helper to simplify the accepted answer:

@model bool?

<div data-ui="buttonset">
    @Radio(true,  "Yes", "Yes")
    @Radio(false, "No",  "No")
    @Radio(null,  "N/A", "NA")
</div>

@helper Radio(bool? buttonValue, string buttonLabel, string buttonId)
{
    Dictionary<string, object> attrs = new Dictionary<string, object>(); 

    // Unique button id
    string id = ViewData.TemplateInfo.GetFullHtmlFieldId("") + buttonId;

    attrs.Add("id", id);

    // Check the active button
    if (Model == buttonValue)
    {
        attrs.Add("checked", "checked");
    }

    @Html.RadioButtonFor(m => m, buttonValue, attrs) <label for="@id">@buttonLabel</label>
}

Answer 6

using Canvas example above I built a customization model and view so you can control the values via a model and edit them in code, bools aren't always a yes/no/(n/a) so Here's how it looks in MVC5.

using a generic model for the nullable bool

public class Customisable_NullableRadioBool
    {
        public bool? Result { get; set; }
        public string TrueLabel { get; set; }
        public string FalseLabel { get; set; }
        public string NullLabel { get; set; }
        public string AttributeTitle { get; set; }
    }

Here's the CSHTML to be stored in: ~/Views/Shared/EditorTemplates/Customisable_NullableRadioBool.cshtml

@model Customisable_NullableRadioBool
@Model.AttributeTitle<br />
<div class="control-group">
    <label>
        @Html.RadioButtonFor(x => x.Result, "", !Model.Result.HasValue ? new { @checked = true } : null)
        <span>@Model.NullLabel</span>
    </label>
    <br />
    <label>
        @Html.RadioButtonFor(x => x.Result, true, Model.Result.GetValueOrDefault() ? new { @checked = true } : null)
        <span>@Model.TrueLabel</span>
    </label>
    <br />
    <label>
        @Html.RadioButtonFor(x => x.Result, false, Model.Result.HasValue && !Model.Result.Value ? new { @checked = true } : null)
        <span>@Model.FalseLabel</span>
    </label>
</div>

And then you can reference the generic class and the editor template through the rest of your project and render the editor template like this.

@Html.EditorFor(m => m.YourCustomisable_NullableBool, "Customisable_NullableRadioBool")

And the rendered output examples