How do I handle server side validation error if I have a form running inside a jQuery UI dialog?

Question

I have the following code in my controller after the user posts the form but if the validation fails (_applicationValidator.Validate), I normally reload the "Edit" view but in this case I want to keep the dialog open and simply show these errors inside the dialog.

Controller Code:

  [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Update(ApplicationUpdater applicationUpdater_)
    {
        if (_applicationValidator.Validate(applicationUpdater_, ModelState, ValueProvider))
        {
            _repo.UpdateApplication(applicationUpdater_);
            ApplicationsViewModel vm = new ApplicationsViewModel();
            vm.Applications = _repo.GetApplications();
            return View("Index", vm);
        }
        else
        {
            ApplicationViewModel vm = GetApplicationVM();
            return View("Edit", vm);
        }
    }

View Code (jQuery)

 $(".showEditPopup").click(function() {
            $.post("Applications/ShowEdit",
                { recnum: $(this).parents('tr:first').attr("recnum") },
                function(htmlResult) {
                    $("#EditUserControlDiv").remove();
                    $("#container").append(htmlResult);
                    $("#container select[multiple]").asmSelect();
                    $("#EditUserControlDiv").dialog(
                    {
                        height: 675,
                        width: 650,
                        modal: true
                    }
                    );
                }
           );
        });

Answer 1

As said

But in this case i want to keep the dialop open and simply show these errors inside the dialog

Ok.

After openning the dialog, you have to

• hide previous error message

...

open: function(event, ui) {
    $(".error").css("display", "none");
}

After clicking dialog button, you have to

• disable JQuery UI
• Show "loading..." image
• Send form

...

$("#loading").css("display", "block");

panel.dialog("disable");

panel.dialog("option", "disabled", true);

After response is loaded (You can use JSON as response), you have to

• Check whether it has errors.

...

// var response plays the role of JSON response

var response = {
    "errors":[
        {
            "property-name":"name",
            "error":"Name is required"
        },
        {
            "property-name":"age",
            "error":""
        }
    ]
};

var hasErrors = false;

for(var i = 0; i < response.errors.length; i++) {
    if(response.errors[i].error != "") {
         hasErrors = true;

         $("#" + response.errors[i]["property-name"] + "-error")
           .text(response.errors[i]["error"])
           .css("display", "block");
    }
}

if(!hasErrors) {
    panel.dialog("close");

    alert("success form!");
} else {
    panel.dialog("enable");

    panel.dialog("option", "disabled", false);
}

Here you can see in Action

Notice you have a default behavior. So you can put it inside a external function

Answer 2

Most convenient:

• Disable all input elements
• Do an Ajax post to the Update function
• Handle the server response in your UI. E.g. closing the jQuery UI form, or showing validation errors.

---

Change your Update function to return some wrapper object like:

return new { Succeeded = false, ValidationMessages = new [] { "Incorrect username" } };

$.post(/* postdata */, function(resp) {
     if(resp.Succeeded) //close jQuery UI dialog
     else {
         for(var i = 0; i < resp.ValidationMessages; i++) alert(resp.ValidationMessages[i]));
     }
});

You can build your postdata, by quering all input/textarea etc. elements, and saving them into an array, something like (untested):

var data = [];    
$('input').each(function() {
    data.push([ $(this).id, $(this).val() ]);
});