ASP.NET MVC 4 form post to url - asp.net-mvc-4

Only just started using MVC 4 & I am not sure how to do the following.
I have a page that displays a list of blog articles '/blog', this page also contains a select list with a list of dates, selecting a date should auto post the form to a URL like '/blog/date/20-05-2015' this URL routes to a ActionResult in a controller, which returns a list of blog articles from that date.
I dont know how to get my form to automatically post to a URL like '/blog/date/20-05-2015'
ROUTE:
routes.MapRoute(
"blogsByDates",
"blog/date/{date}",
new { controller = "Blog", action = "IndexByDate" }
);
CONTROLLER
public ActionResult IndexByDate(DateTime date)
{
var query = from c in db.Blogs
where c.PublishDate >= date
select c;
return View("Index", query.ToList());
}
VIEW (PARTIAL)
#using (Html.BeginForm())
{
<select name="ddlMonth" id="ddlMonth">
<option value="01-06-2012">June 2012</option>
<option value="01-05-2012">May 2012</option>
</select>
}

You'll have to use jQuery or something to change the ACTION attribute of your form. There's no other way to change the destination a form posts to. Though why you're using a form when you're not sending any special data to the server. Just make it a list of clickable links.

Related

Asp.Net Core 2.0: Razor view isn't matching a string id route

This line only works when my id is numeric.
<a asp-page="./Edit" asp-route-id="#item.Id">Edit</a>
On one page I need it to be a string.
When it is a number it is generated as
Edit
But when it is a string it is generated as
Edit
I tried hardcoding the value like this Edit, but it just got a 404.
I am using the default routing with my ASP.NET Core 2.0 Razor page...
app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller}/{action=Index}/{id}");
});
And the edit page is set up like...
public async Task<IActionResult> OnGetAsync(string id)
How can I fix this?
At the top of my edit page was the line...
#page "{id:int}"
I had to change this to
#page "{id:alpha}"
and at that point the route was matched.
Thank you to this page https://exceptionnotfound.net/asp-net-core-demystified-razor-pages/ by Matthew P Jones, which gave an easy to understand explanation of routing with the new Razor pages.
In case of string simply use:
#page "{id?}
and you should be able to retrieve the value of id (string) in respective method.

Post back Errors in MVC 4

In regular Asp.Net, when you want to post an error, for ex, a duplicate ID, I use Panels for controls, error message labels, etc. I was wondering, how to achieve the same using MVC 4.
Currently, on my Index page, I have an Id, Name & Address column and a Submit button. My HTTPPOST ActionResult here:
[HttpPost]
public ActionResult Index(Person p)
{
if (ModelState.IsValid)
{
PersonInfo pi = new PersonInfo();
var duplicate = from d in db.PersonInfoes
where d.Id == p.Id
select d;
if (duplicate.Any())
{
return View("Duplicate");
}
else
{....}
When I enter a duplicate Id, upon submitting the page, I need to post to the same view ("Index") page to let user know that there is an Id already, but currently, I am redirecting to a different view to let user know as a duplicate, and I dont think this is the right way to do this. I am learning MVC, btw and hence this doubt. My duplicate cshtml here:
#{
ViewBag.Title = "Duplicate";
}
<h2>Duplicate</h2>
<h3>Duplicate ID found !!</h3>
<p>Please correct the ID and re-enter !</p>
<br/><br/>
#Html.ActionLink("Back to Data Entry","Index")
Any pointers would help.
You can return to the same view. You should consider adding an error to the model state dictionary so that you can show that in the UI.
[HttpPost]
public ActionResult Index(Person p)
{
if (ModelState.IsValid)
{
var duplicate= db.PersonInfoes.Where(s=>s.Id== p.Id);
if (duplicate.Any())
{
ModelState.AddModelError(string.Empty,"Duplicate found");
return View(p);
}
// to do : Your existing code
}
return View(p);
}
Just make sure you are calling the ValidationSummary method in your Index view to show this error message.
#model Person
#using (Html.BeginForm())
{
#Html.ValidationSummary(false)
<!-- Your form fields goes here-->
<input type="submit" />
}

Using Ajax to update ViewBag data ASP.NET MVC4

I'm currently have 2 class call City and District (1 to many relationship, respectively) .In my view I have 2 dropdown list, one for all the cities and the other for the districts (populated by using ViewBag). When a city is selected, I want the dropdown list for district to display only districts of that city without reloading the whole view. I had used Ajax before but only to re-populate data for model and not ViewBag. So how can I do it using Ajax and ViewBag ?
you can't repopulate the ViewBag itself.
I don't know if this is the best way but I would have done it the following way:
HTML:
<div>
<select id="city">
options
</select>
</div>
<div id="district-select">
<select>
</select>
</div>
JS:
$("#city").change(function() {
var id = $(this).val();
$.ajax({
type: "GET",
url:"/CONTROLLER/GetDistrictsByCity",
data: {cityId: id},
success: function(data) {
$("#district-select").html(data);
}
});
});
ACTION:
public ActionResult GetDistrictsByCity(Guid cityId){
//GET Districts that is linked to the cityId
return PartialView("_DistrictsByCity", model);
}
and then in the view "_DistrictsByCity" all you create is the dropdownlist. that html will then be taken and placed inside the div with the id "district-select"
Let me know if anything is unclear
it's bad idea to use ViewBag instead of StronglyTyped (Model)
so declare a ViewModel First and then pass your data to View via ViewModel

What ActionResult should you return to update just the ActionLink text?

I'm using MVC4 with Entity Framework and like many people I'm new to MVC and trying to get my head around the design patterns.
I have a partial view that displays a list of sessions followed by actionlinks allowing the authenticated member to book into the sessions.
Note: for clarity, I've chopped out most of the code, if a member is booked into a session, it displays "Booked" instead of the action link.
#using OnlineBookings.Website.Models
#{ DateTime currentDate = DateTime.MinValue.Date; }
<form method="post" action="~/Controllers/BookSessionController.cs">
#foreach (SessionsWithBookingInformation s in Model)
{
<p>#s.StartTime.ToString("t")
#s.Description
#Html.ActionLink(
"Book",
"BookSession",
new { sessionId = s.SessionId }
)
</p>
}
</form>
This then displays as part of a larger view:
The actionlinks pass the guid of the session to be booked through to the following function in my controller, which retrieves the memberId from the cookie and uses Entity Framework to create a booking for that member and session.
public ActionResult BookSession(Guid sessionId)
{
using (var db = new OnlineBookingsEntities())
{
// see if the member id is stored in a cookie
if (Request.Cookies["memberId"] != null)
{
var memberId = new Guid(Request.Cookies["memberId"].Value);
db.Bookings.Add(new Booking
{
BookingId = Guid.NewGuid(),
MemberId = memberId,
SessionId = sessionId,
BookingTime = DateTime.Now
});
db.SaveChanges();
}
}
// this refreshes the entire page
/// is there a better way to just replace the actionlink they clicked on?
return RedirectToAction("Index", "Home");
}
All this is working nicely and bookings are being effectively recorded.
But, I'm trying to figure is if the return from the BookSession function can just update the actionlink text.
Ideally, on success, I want to replace the ActionLink in my partial view with the word "Booked" and on failure I want to replace it with the failure condition like "Session full".
Or I could just update my partial view, because that will do the same thing.
Am I missing something simple here? Or, am I barking up entirely the wrong tree?
Your question is great and really well explained, but it's also a little vague since it's a bit of a "What should I do?" question. Here are a few options that might help you develop a solution.
Redisplay the same view. Return whichever view the user was on for them to submit the link. This will look like a simple refresh.
return View();
Submit the request via AJAX and update via a partial view. Put an id tag on a span or similar HTML element with an individual booking's details inside. Submit the request with AJAX, perhaps via #Ajax.ActionLink, and have your action return a partial view.
return PartialView("_OnlineBookingPartial", model);
Once your partial view is returned, update the specific booking with the data returned.
Use AJAX again, but return JSON. Another way might be that you use AJAX again but instead you return JSON and do something with it. You could, for example, return text in which you would replace Book with; i.e. "Session full" or "Booked!".
return new JsonResult
{
Data = "Booked!"
}
Personally, I'd probably use AJAX to update with a non-AJAX (non-Javascript) fallback.
You can do this by using #Ajax.ActionLink and checking if the request is AJAX or not inside your controller action.
if (Request.IsAjaxRequest) {
return PartialView("_OnlineBookingPartial", model);
}
return View();
This means that if the browser has Javascript enabled and supports AJAX, it will be used and the whole process will be seamless and instant for the user. If Javascript is disabled, the page will simply refresh.

unobtrusive validation not working with dynamic content

I'm having problems trying to get the unobtrusive jquery validation to work with a partial view that is loaded dynamically through an AJAX call.
I've been spending days trying to get this code to work with no luck.
Here's the View:
#model MvcApplication2.Models.test
#using (Html.BeginForm())
{
#Html.ValidationSummary(true);
<div id="res"></div>
<input id="submit" type="submit" value="submit" />
}
The Partial View:
#model MvcApplication2.Models.test
#Html.TextAreaFor(m => m.MyProperty);
#Html.ValidationMessageFor(m => m.MyProperty);
<script type="text/javascript" >
$.validator.unobtrusive.parse(document);
</script>
The Model:
public class test
{
[Required(ErrorMessage= "required field")]
public int MyProperty { get; set; }
}
The Controller:
public ActionResult GetView()
{
return PartialView("Test");
}
and finally, the javascript:
$(doument).ready(function () {
$.ajax({
url: '/test/getview',
success: function (res) {
$("#res").html(res);
$.validator.unobtrusive.parse($("#res"));
}
});
$("#submit").click(function () {
if ($("form").valid()) {
alert('valid');
return true;
} else {
alert('not valid');
return false;
}
});
The validation does not work. Even if I don't fill any information in the texbox, the submit event shows the alert ('valid').
However, if instead of loading dynamically the view, I use #Html.Partial("test", Model) to render the partial View in the main View (and I don't do the AJAX call), then the validation works just fine.
This is probably because if I load the content dynamically, the controls don't exist in the DOM yet. But I do a call to $.validator.unobtrusive.parse($("#res")); which should be enough to let the validator about the newly loaded controls...
Can anyone help ?
If you try to parse a form that is already parsed it won't update
What you could do when you add dynamic element to the form is either
You could remove the form's validation and re validate it like this:
var form = $(formSelector)
.removeData("validator") /* added by the raw jquery.validate plugin */
.removeData("unobtrusiveValidation"); /* added by the jquery unobtrusive plugin*/
$.validator.unobtrusive.parse(form);
Access the form's unobtrusiveValidation data using the jquery data method:
$(form).data('unobtrusiveValidation')
then access the rules collection and add the new elements attributes (which is somewhat complicated).
You can also check out this article on Applying unobtrusive jquery validation to dynamic content in ASP.Net MVC for a plugin used for adding dynamic elements to a form. This plugin uses the 2nd solution.
As an addition to Nadeem Khedr's answer....
If you've loaded a form in to your DOM dynamically and then call
jQuery.validator.unobtrusive.parse(form);
(with the extra bits mentioned) and are then going to submit that form using ajax remember to call
$(form).valid()
which returns true or false (and runs the actual validation) before you submit your form.
Surprisingly, when I viewed this question, the official ASP.NET docs still did not have any info about the unobtrusive parse() method or how to use it with dynamic content. I took the liberty of creating an issue at the docs repo (referencing #Nadeem's original answer) and submitting a pull request to fix it. This information is now visible in the client side validation section of the model validation topic.
add this to your _Layout.cshtml
$(function () {
//parsing the unobtrusive attributes when we get content via ajax
$(document).ajaxComplete(function () {
$.validator.unobtrusive.parse(document);
});
});
test this:
if ($.validator.unobtrusive != undefined) {
$.validator.unobtrusive.parse("form");
}
I got struck in the same problem and nothing worked except this:
$(document).ready(function () {
rebindvalidators();
});
function rebindvalidators() {
var $form = $("#id-of-form");
$form.unbind();
$form.data("validator", null);
$.validator.unobtrusive.parse($form);
$form.validate($form.data("unobtrusiveValidation").options);
}
and add
// Check if the form is valid
var $form = $(this.form);
if (!$form.valid())
return;
where you are trying to save the form.
I was saving the form through Ajax call.
Hope this will help someone.
just copy this code again in end of modal code
<script src="~/Scripts/jquery.unobtrusive-ajax.min.js"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.min.js"></script>
;)