Why is my hidden input writing: value="value" instead of true/false?
This behaviour changed between MVC3 and MVC4. In MVC3, if you have:
<input name="somefield" type="hidden" someprop="@(SomeBooleanExpression)"/>
it would write very literally:
<input name="somefield" type="hidden" someprop="True"/>
However, in MVC4, it follows the "checkbox" etc rules, so if the value is true
you get:
<input name="somefield" type="hidden" someprop="someprop"/>
and if it is false
it is omitted completely:
<input name="somefield" type="hidden"/>
To get around this, consider .ToString()
:
<input name="somefield" type="hidden"
someprop="@(SomeBooleanExpression.ToString())"/>
which then follows string rules rather than boolean rules.
Marc Gravell
e-mail: [email protected] blog: http://blog.marcgravell.com/ twitter: @marcgravell C# programmer and MVP, with a keen interest in all things code. Particular areas: Dapper (dapper) StackExchange.Redis (stackexchange.redis) Protocol Buffers (protobuf-net)
Updated on June 05, 2022Comments
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Marc Gravell almost 2 years
I have an MVC4 site, with (as part of a hidden form):
<input name="somefield" type="hidden" value="@ViewBag.Test"/>
The value of
ViewBag.Test
istrue
. The form field is posting to an input parameter of the form:public ActionResult SomeAction(bool somefield = false, ...)
but
somefield
is alwaysfalse
. Upon investigating, I see that the source code has:<input name="somefield" type="hidden" value="value"/>
However, I know this used to work. What has happened, and what can I do?