ASP.net MVC Validation Hook

Question

I have the following view in ASP.net MVC 3:

@model Models.CreateProjectViewModel

<script type="text/javascript" src="@Url.Content("~/Scripts/jquery.validate.min.js")"></script>
<script type="text/javascript" src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")"></script>

@using( Html.BeginForm() ) {
    @Html.TextBoxFor(m => m.ProjectName)
    @Html.ValidationMessageFor(m => m.ProjectName)

    <p>
        <input type="submit" value="Save" />
    </p>
}

I am using unobtrusive javascript with jQuery and the Fluent Validation framework.

When I click the Save button and validation fails, is there some event I can hook into to call some custom javascript?

function validationFailed() {
    // do something here only if validation failed
}

How would I tie into the validation so that when it failed (and only if it failed) I could call my validationFailed() function.

Solution

As jQuery/Validation docs says, you could use invalidHandler to react when an invalid form is submitted.

But since MVC unobtrusive validation instantiates the Validation itself, you have to hook this event later.

Using exactly the same mechanism as the jQuery/Validation does: you could bind your code to the form elements custom event 'invalid-form.validate', witch corresponds to the invalidHandler!

$(document).ready(function() {
    $('#myform').bind('invalid-form.validate',function(){
        alert('invalid form!');
    });
});

to give your form an id use:

@using (Html.BeginForm(null, null, FormMethod.Post, new { id = "myform" })) {
} 

---

Update:

An alternative way to get the existing validation object is calling validate() on the form. If a validator for this form was already created, it will be returned:

Edit: after initialization occured, changing .settings.invalidHandler is too late for binding. So the following snippet will not work [anymore] unless you re-init the validator.

$(document).ready(function() {
    var existingValdiation = $("#myform").validate();
    //the settings property corresponds to the options parameter
    existingValdiation.settings.invalidHandler = function (form) {
        alert('invalid form!');
    };
    // not recommended:
    // re-init would bind settings.invalidHandler to 'invalid-form.validate'
    // existingValdiation.init();
});

Comments

[Rafael Merlin]

Thank you. First option was perfect for me. =-)

[Jernej Novak]

First option worked. Second did not. Should edit alternative or delete it? Thanks for the first one.