Question

I have a search form & knockout-based grid for results. When search is performed, there is some server-side validation taking place on asp.net mvc, and if model state is not valid, it is returning list of model errors via JSON.

I have jQuery validation already set up, and default validations (regex, required etc) are automatically mapped using jquery.unobtrusive plugin.
I found $.validate().showErrors({prop:error}) as a way to dynamically show errors based on json response from server, but I’m thinking that this is not proper way to use it for displaying server validation messages, as field cannot be reset afterwards (input-validation-error class is not removed).

I need a working method for setting & resetting errors on client, if such exists in $.validate.

There is example with my problem on jsFiddle: http://jsfiddle.net/goranobradovic/ughCm/

To reproduce it, click add error, then remove error, input stays red.

This is because showErrors function does not add any rules which are triggered by validation, so field stays ‘valid’ and it is not in elements() list which is used in resetForm to remove input-validation-error class from invalid fields.

Basically, I want simple way to add/remove validation rule with custom message which is never satisfied on client, to avoid form submission when I set error manually and having to remove invalid class after removing error message.

Answer 1

I have solved this by overriding showErrors function in jQuery validator with my own, which is compatible with unobtrusive-generated validation spans, and cleaning up valid fields which have invalid class. It is not very nice workaround but it works.

Here is jsfiddle with solution: http://jsfiddle.net/goranobradovic/ughCm/5/

UPDATE: As link to external site is not proper answer according to site guidelines, I’m adding code sample here. For anyone already familiar with jQuery validation, just look at two lines of code in showErrors function. I assigned it to validator with validator.settings.showErrors = showErrors;.

HTML:

<form id="experiment" action="/" method="post">

<fieldset>
  <legend></legend>
        <div class="editor-label">
          <label for="Email">Email</label>
        </div>
        <div class="editor-field">
<input data-val="true" data-val-email="&amp;#39;Email&amp;#39; not valid email address." data-val-required="&amp;#39;Email&amp;#39; is mandatory." id="Email" name="Email" type="text" value=""><span class="field-validation-valid" data-valmsg-for="Email" data-valmsg-replace="true"></span>        
        </div>
        <div class="editor-label">
          <label for="FirstName">First name</label>
        </div>
        <div class="editor-field">
          <input class="text-box single-line" id="FirstName" name="FirstName" type="text" value="">
          <span class="field-validation-valid" data-valmsg-for="FirstName" data-valmsg-replace="true"></span>
        </div>

        <div class="editor-label">
          <label for="LastName">Last name</label>
        </div>
        <div class="editor-field">
          <input class="text-box single-line" id="LastName" name="LastName" type="text" value="">
          <span class="field-validation-valid" data-valmsg-for="LastName" data-valmsg-replace="true"></span>
        </div>   
</fieldset>
    <p>
        <button type="submit" class="save ui-button ui-widget ui-state-default ui-corner-all ui-button-text-icon-secondary" value="Save" role="button" aria-disabled="false"><span class="ui-button-text">Save</span><span class="ui-button-icon-secondary ui-icon ui-icon-disk"></span></button>

    </p>
</form>
<br/>

<button id="add">Add error</button>
<button id="remove">Remove error</button>

<br/>
<br/>
Debug:
<div id="debug"></div>

JavaScript:

var validator = {};

function addError(e) {
    validator.showErrors({
        "FirstName": "test error"
    });
}

function removeError(e) {
    validator.showErrors({
        "FirstName": null
    });
    fixValidFieldStyles($("form"), validator);
}

$(document).ready(function() {
    var $form = $("#experiment");
    // prevent form submission
    $form.submit(function(e) {
        e.preventDefault();
        return false;
    });
    $("#add").click(addError);
    $("#remove").click(removeError);
    $("#debug").html("<h1>Validator properties:</h1>");
    validator = $form.validate();
    validator.settings.showErrors = showErrors;
    for (var i in validator) {
        var row = $("<span></span>").html(i).append("<br/>");
        $("#debug").append(row);
    }
});


function showErrors(errorMessage, errormap, errorlist) {
    var val = this;
    errormap.forEach(function(error, index) {
        val.settings.highlight.call(val, error.element, val.settings.errorClass, val.settings.validClass);
        $(error.element).siblings("span.field-validation-valid, span.field-validation-error").html($("<span></span>").html(error.message)).addClass("field-validation-error").removeClass("field-validation-valid").show();
    });
}

function fixValidFieldStyles($form, validator) {
    var errors = {};
    $form.find("input,select").each(function(index) {
        var name = $(this).attr("name");
        errors[name] = validator.errorsFor(name);
    });
    validator.showErrors(errors);
    var invalidFields = $form.find("." + validator.settings.errorClass);
    if (invalidFields.length) {
        invalidFields.each(function(index, field) {
            if ($(field).valid()) {
                $(field).removeClass(validator.settings.errorClass);
            }
        });
    }
}