Perform unobtrusive JQuery form validation without form submit

Question 1

So I got the answer to the above question. The trick is to set the button type="button" in stead of "submit".

So, for anyone else struggling with this, here is an example of how to get it to work...

Your knockout ViewModel:

$(document).ready(
    function () {

        var Crime = function (CaseNumber, DateOfIncident, Description) {
            this.CaseNumber = CaseNumber;
            this.DateOfIncident = DateOfIncident;
            this.Description = Description;
        }

        var crimes = function (items) {
            var self = this;
            //Data
            self.items = ko.observableArray(items)

            //operations
            self.addCrime = function () {
                if ($("#AddCrimeForm").valid()) {
                    self.crime = new Crime($("#CaseNumber").val(), $("#DateOfIncident").val(), $("#Description").val());
                    //var JSONObj = { CaseNumber: $("#CaseNumber").val(), DateOfIncident: $("#DateOfIncident").val(), Description: $("#Description").val() };
                    self.items.push(this.crime);

                    $("#CaseNumber").val("");
                    $("#DateOfIncident").val("");
                    $("#Description").val("");
                }
            }

            self.removeCrime = function (item) {
                self.items().remove(item);
            }

        }

        var initialData = new Array();
        ko.applyBindings(crimes(initialData), $("#CrimeList")[0])
    }
);

And here is the corresponding HTML:

<form id="AddCrimeForm">
    <div class="panel panel-success">
        <div class="panel-heading">
            <div class="form-horizontal">
                <div class="row">
                    <div class="col-lg-11">Add a crime incident to the list</div>
                    <div class="col-lg-1">
                        <button type="button" class="btn btn-success btn-xs" onclick="addCrime();"><i class="fa fa-plus"></i> Add</button>
                    </div>
                </div>
            </div>
        </div>

        <div class="panel-body">
            <div class="form-horizontal">
                <div class="row">
                    <div class="col-lg-6">
                        <input data-val="true" data-val-number="The field Id must be a number." data-val-required="The Id field is required." id="Id" name="Id" type="hidden" value="">
                        <div class="form-group">
                            <label class="control-label col-md-4" for="CaseNumber">Case Number</label>
                            <div class="col-md-8">
                                <input class="form-control text-box single-line" data-val="true" data-val-required="The Case Number field is required." id="CaseNumber" name="CaseNumber" type="text" value="">
                                <span class="field-validation-valid" data-valmsg-for="CaseNumber" data-valmsg-replace="true"></span>
                            </div>
                        </div>
                        <div class="form-group">
                            <label class="control-label col-md-4" for="DateOfIncident">Date Of Incident</label>
                            <div class="col-md-8">
                                <input class="form-control text-box single-line valid" data-val="true" data-val-required="The Date of Incident field is required." id="DateOfIncident" name="DateOfIncident" type="date" value="">
                                <span class="field-validation-valid" data-valmsg-for="DateOfIncident" data-valmsg-replace="true"></span>
                            </div>
                        </div>
                    </div>
                    <div class="col-lg-6">
                        <div class="form-group">
                            <label class="control-label col-md-4" for="Description">Description</label>
                            <div class="col-md-8">
                                <textarea class="form-control text-box multi-line" data-val="true" data-val-required="The Description field is required." id="Description" name="Description"></textarea>
                                <span class="field-validation-valid" data-valmsg-for="Description" data-valmsg-replace="true"></span>
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
</form>

<table class="table table-striped table-hover " id="CrimeList">
    <thead>
        <tr>
            <th>Case Number</th>
            <th>Date of Incident</th>
            <th>Description</th>
            <th></th>
        </tr>
    </thead>
    <tbody data-bind="foreach: items">
        <tr>
            <td data-bind="text: $data.CaseNumber">Column content</td>
            <td data-bind="text: $data.DateOfIncident">Column content</td>
            <td data-bind="text: $data.Description" style="text-wrap: normal">Column content</td>
            @*<td></td>
                <td></td>
                <td></td>*@
            <td>...</td>
        </tr>
    </tbody>
</table>

Once again - take notice that the "Add" button's type has been set to "button" and NOT "submit".

Hope this helps the rest of all you coding peeps out there!

Question 2

I am in this moment trying to do something similar.

my idea at begining was same as yours, but then I made some changes because it is hard to do complex validation with data annotations. With complex I mean that a record do not repeat on a data base, or a custom format on an input.

So I went for FluentValidation, the problem is that fluent validation is not always working in unobtrusive validation. So what I am doing now is this.

hope this helps you and if you find something that could be better please let me know:

my model with its validation:

    public class BUCashFlow
{
    public int Id { get; set; }
    [Display(Name = "Concepto")]
    public string Text { get; set; }
    [Display(Name = "Valor")]
    public double Value { get; set; }
    public CashFlowType CashFlowType { get; set; }
    [Display(Name = "Cuenta")]
    public int AccountId { get; set; }
    public string User { get; set; }

    public virtual Account Account { get; set; }
}

public class BuCashFlowVal : AbstractValidator<BUCashFlow>
{
    public BuCashFlowVal()
    {

        RuleFor(p => p.Text)
            .NotEmpty().WithMessage(ValHelper.Messages.Required);
        RuleFor(p => p.Value)
            .NotEmpty().WithMessage(ValHelper.Messages.Required);
        RuleFor(p => p.AccountId)
            .NotEmpty().WithMessage(ValHelper.Messages.Required);
    }
}

I am using web api too, so here is my web api controller, where i Validate my new BUCashFlow model

        // POST api/BUCashFlows
    [ResponseType(typeof(BUCashFlow))]
    public IHttpActionResult PostBUCashFlow(BUCashFlow bucashflow)
    {
        ValidationResult ValRes = new BuCashFlowVal().Validate(bucashflow);
        if (!ValRes.IsValid)
        {
            return BadRequest(ValRes.Errors[0].ErrorMessage);
        }
        bucashflow.User = User.Identity.GetUserId();
        bucashflow.CashFlowType=CashFlowType.Purchase;
        db.BuCashFlows.Add(bucashflow);
        db.SaveChanges();

        return CreatedAtRoute("DefaultApi", new { id = bucashflow.Id }, bucashflow);
    }

finally to display my errors in js/ko i am doing this:

            self.addExpense = function(selector) {
            $.ajax({
                type: 'POST',
                url: '@ViewBag.ApiBUExpenses',
                data: $(selector).serialize()
            }).done(function(o) {
                self.expenses.push(new ExpenseVM(self, o.Id, o.Text, o.Value, o.AccountId));
            }).fail(function (o) {
                $(selector).find('.val').html(  '<div class="alert alert-warning alert-dismissable">' +
                                                    '<button type="button" class="close" data-dismiss="alert" aria-hidden="true">&times;</button>' +
                                                    '<strong>Warning!</strong> ' + o.responseJSON.Message +
                                                '</div>');
            });
        };

and my html form that was serialized in this ajax Call:

            <form id="new-expense-form" data-bind="submit: addExpense">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                <h4 class="modal-title" id="myModalLabel">Agregar Nuevo Gasto</h4>
            </div>
            <div class="modal-body">
                <div class="form-group">
                    <label class="control-label">Concepto</label>
                    <input name="Text" type="text" class="form-control" />
                </div>
                <div class="form-group">
                    <label class="control-label">Valor</label>
                    <input name="Value" type="text" class="form-control" />
                </div>
                <div class="form-group">
                    <label class="control-label">Cuenta</label>
                    <i data-bind="visible: isLoadingAccounts" class="fa fa-refresh fa-spin pull-right"></i>
                    <select name="AccountId" class="form-control" data-bind="options: accounts, optionsText: 'name', optionsValue: 'Id', optionsCaption: 'Cuenta'"></select>
                </div>
                <div class="val"></div>
            </div>
            <div class="modal-footer">
                <button class="btn btn-default-pnl btn-circle-m" title="Guardar Gasto">
                    <i class="fa fa-check"></i>
                </button>
            </div>
        </form>

What you think about this approach?

If FoolProof works as espected

thanks for sharing this library, now if this works you just have to change the ajax call this way:

self.addExpense = function(selector) {
    $(selector).validate()
    if ($(selector).valid()) {
            $.ajax({
                type: 'POST',
                url: '@ViewBag.ApiBUExpenses',
                data: $(selector).serialize()
            }).done(function(o) {
                self.expenses.push(new ExpenseVM(self, o.Id, o.Text, o.Value, o.AccountId));
            })
    }
};

Update

I saw your library and I think it wonrt work, if it doesnt, you always can duplicate your validtion and use KnockoutValidation