bool property without Required attribute is required

Question

have a simple ViewModel with three properties like so:

public bool RememberMe { get; set; }

In my view I have a simple @Html.CheckBoxFor(p => p.RememberMe) I am using Client Side validation enabled using Html.EnableClientValidation();

Why is this being set as a required field?

Answer 1

Try a nullable bool.

public bool? RememberMe { get; set; }

With reference types there are a number of default validation rules applied. If a reference type is not nullable, it becomes required by default. The best illustration of this is if you use a textbox to display some properties (not something you would do in your site, but good for testing purposes):

Model:

public bool? MyBool { get; set; }
public int MyInt { get; set; }

View:

 @Html.TextBoxFor(p => p.MyBool)
 @Html.TextBoxFor(p => p.MyInt)

You can see from a view source what happens on the page:

<input id="MyNullBool" name="MyNullBool" type="text" value="">
<input data-val="true" data-val-required="The MyBool field is required." id="MyBool" name="MyBool" type="text" value="False">
<input data-val="true" data-val-number="The field MyInt must be a number." data-val-required="The MyInt field is required." id="MyInt" name="MyInt" type="text" value="0">

The nullable bool has no validation attributes, whereas the bool has a data-val-required tag. The int has a data-val-required tag and a data-val-number attribute

Of course, on a checkbox this is all pretty redundant as it can only be checked (true) or not checked (false) so a required tag isn't much use.