.Net Core Razor Pages - Refresh fields after post -unobtrusive ajax - ajax

I have created a .Net Core Razor Pages Application. There are two input fields and a submit button in a razor page. When I click on the button, the numbers in the input fields needs to be incremented. There is a message ‘Hello World’ which is assigned in the OnGet() method.
To keep the message, I used unobtrusive ajax. In this case, the message will remain there but the numbers will not increment. Is there any way to refresh the numbers without writing code in ajax call back method to assign values individually to each element?
Ultimately, my aim is to post a portion of a page and refresh the bind data in the fields on post back without assigning values to the controls individually in ajax call back. Code sample is given below
Note:Need to do this without the whole page relaod.
Index.cshtml
#page
#model IndexModel
#{
ViewData["Title"] = "Home page";
}
<h1>#Model.Message</h1>
<form method="post" data-ajax="true" data-ajax-method="post" >
<div>
<input type="text" asp-for="Num1" />
<input type="text" asp-for="Num2" />
<input type="submit" value="Submit" />
</div>
</form>
Index.cshtml.cs
public class IndexModel : PageModel
{
[BindProperty]
public int Num1 { get; set; } = 0;
[BindProperty]
public int Num2 { get; set; } = 0;
public string Message { get; set; }
public void OnGet()
{
Message = "Hello World";
GetNumbers();
}
void GetNumbers()
{
Num1 += 1;
Num2 += 5;
}
public IActionResult OnPost()
{
GetNumbers();
return Page();
}
}

ModelState.Remove("Nmu1");
ModelState.Remove("Nmu2");
Similarly to ASP.NET WebForms, ASP.NET Core form state is stored in ModelState. After posting, the form will be loaded with the the binding values, then updated with ModelState. So there is a need to clear the values within ModelState, otherwise the values will be overwritten.

Related

How do you deal with Razor Pages PageRemote validation on 'loaded' data (e.g edit ViewModel Page)?

I am probably missing the obvious, but nevertheless a little stuck with PageRemote validation. Like a lot of us, I am following Mike’s helpful tutorial on the subject: https://www.mikesdotnetting.com/article/343/improved-remote-validation-in-razor-pages
I won’t copy his code here, as it is easy to follow, and works exactly as demonstrated. Great for a ‘Create User’ page!
My problem is though, when applying it to an ‘Edit User’ page, then I have hit a couple snags. In the OnGet() I load the ‘User’ from a QueryString, and populate the form, including the remote validated field. If I touch no fields, and straight away hit the submit button, it doesn’t trigger the submit’s OnPostSubmit() handler, but the PageRemote’s validation OnPost() instead (as presumably the field is dirty, even if the user didn’t do it).
So how do I make sure the submit button fires as expected, in this scenario? According to my break point, it never fires the OnPostSubmit() handler, in this scenario.
Following this scenario, that PageRemote’s OnPost returns ‘true’ (as nothing changed, and everything is still valid), but something else seems to be going on, as a SelectList that is normally loaded OnGet() is now empty, and means the form is now not complete. If before I click the submit button, I enter any of the form’s fields, and force the PageRemote to normally fire, my SelectList is fine. The loss of loaded SelectList values being lost, is only when the PageRemote fires when immediately clicking submit without touching any fields. Why does it behave differently? Surely I am not suppose to be reloading data in this PageRemote validation OnPost() handler, especially in the normal scenario’s, I don’t have to…
I hope this makes sense, and I hope I have not upset anyone by not putting any code up. I am happy to edit my questions with some code, but it is 99% as in Mike’s article. The only difference I have, is populating the ViewModel and SelectList OnGet().
EDIT for code:
#page
#model Redbook.Pages.Test.EditAccountModel
#{
ViewData["Title"] = "EditAccount";
}
<h1>EditAccount</h1>
<form method="post" id="frmUserDetails">
<div class="form-group">
<label class="pt-1">Email</label>
<input id="txtEmail" type="email" inputmode="email" class="form-control" asp-for="Email">
<span class="text-danger" asp-validation-for="Email"></span>
</div>
<div class="form-group">
<label class="pt-1">User Select Option</label>
<select class="form-control" asp-for="UserSelectListOption" asp-items="Model.UserSelectListOptions"></select>
<span class="text-danger" asp-validation-for="UserSelectListOption"></span>
</div>
<button id="btnContinue" type="submit" asp-page-handler="Continue" class="btn btn-outline-info">
Save
</button>
</form>
#section Scripts
{
<script src="~/lib/jquery/dist/jquery.min.js"></script>
#await Html.PartialAsync("_ValidationScriptsPartial")
<script src="~/lib/jquery-ajax-unobtrusive/dist/jquery.unobtrusive-ajax.min.js"></script>
}
CodeBehind
public class EditAccountModel : PageModel
{
[Required(ErrorMessage = "Email Address Required")]
[EmailAddress(ErrorMessage = "Invalid Email Address")]
[PageRemote(
ErrorMessage = "Email/User already in use.",
AdditionalFields = "__RequestVerificationToken",
HttpMethod = "post",
PageHandler = "CheckEmail"
)]
[BindProperty]
public string Email { get; set; }
[Required(ErrorMessage = "User Select List Option Required")]
[BindProperty]
public int UserSelectListOption { get; set; }
public SelectList UserSelectListOptions { get; set; }
public async Task<IActionResult> OnGet()
{
//Normally would pass param (querystring) to load 'user' to edit, but this is just a test!
await Task.CompletedTask;
Email = "joe.bloggs#test.com";
UserSelectListOption = 2;
//Our user form needs a drop down option.
LoadSelectList();
return Page();
}
public async Task<IActionResult> OnPostContinueAsync()
{
if (!ModelState.IsValid)
{
LoadSelectList();
return Page();
}
//Normally we would do something here (e.g get UserID), but again, this is just a test!
await Task.CompletedTask;
//We dont hit this when we first hit submit, unless we pass focus to the 'Email' control first.
//Instead 'OnPostCheckEmail' is triggered only
//Not only that, but when that happens, 'UserSelectListOptions' is empty, so we fail the required validation for that control.
//If we do touch the 'Email' control before submission, validation triggers normally,
//It doesn't affect 'UserSelectListOptions'
//Then we do hit this point successfully.
return Page();
}
public JsonResult OnPostCheckEmail()
{
var existingEmails = new[] { "jane#test.com", "claire#test.com", "dave#test.com" };
var valid = !existingEmails.Contains(Email);
return new JsonResult(valid);
}
public void LoadSelectList()
{
List<SelectListOption> selectListOptions = new List<SelectListOption>();
selectListOptions.Add(new SelectListOption(1, "Option1"));
selectListOptions.Add(new SelectListOption(2, "Option2"));
selectListOptions.Add(new SelectListOption(3, "Option3"));
UserSelectListOptions = new SelectList(selectListOptions, "OptionID", "OptionName");
}
public class SelectListOption
{
public SelectListOption(int optionID, string optionName)
{
this.OptionID = optionID;
this.OptionName = optionName;
}
public int OptionID { get; set; }
public string OptionName { get; set; }
}
}
The "[PageRemote ...]" example didn't work with my bound viewModel; so I created some script to onblur put the email text into my asp-for viewMode.Email input; that way onsubmit, my viewModel.Email has the email value already
enter code here
<input class="viewEmail-input" asp-for="viewModel.Email" />
...
<input asp-for="Email" placeholder="Email" class="email-input" />
$(document).ready(function () {
$('.email-label').on("blur", function () {
var value = $('.email-input').val();
$('.viewEmail-input').val(value);
});
});
I also put my PageRemote into a seperate common cshtml file so more than one razor page can call the same code RemoteValidation_cshtml_cs
Then modified the PageRemote as follows:
enter code here
[PageRemote(
ErrorMessage = "Email Address already exists",
AdditionalFields = "__RequestVerificationToken",
HttpMethod = "post",
PageHandler = "CheckEmail",
PageName = "RemoteValidation"
)]
[Required, EmailAddress]
[RegularExpression(#"^[a-zA-Z0-9_.+-]+#[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$", ErrorMessage = "Invalid Email format")]
[BindProperty]
public string Email { get; set; }
Finally, I notice that there was a database call everytime a character was typed in or deleted from the email input textbox; to prevent this I created a quick routine to verify the passed in email was actually an email address before checking the database; for now, it still checks after typing "c" "o" and "m", but that's only three calls instead of dozens.
enter code here
public async Task<JsonResult> OnPostCheckEmail(string email)
{
// In order to not call the database, check if email is valid email before calling database
// Have to return true... so error is not shown to user; other validation will catch it on submit.
if (!IsValidEmailFormat(email)) return new JsonResult(true);
var user = await _userManager.FindByEmailAsync(email);
if (user == null)
{
return new JsonResult(true);
}
return new JsonResult($"Email { email } is already in use");
}
private bool IsValidEmailFormat(string email)
{
String AllowedChars = #"^[a-zA-Z0-9_.+-]+#[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$";
if (Regex.IsMatch(email, AllowedChars))
{
return true;
}
return false;
}
}

How to bind a list of objects in ASP.NET Core MVC when the posted list is smaller than original?

Using "disabled" attribute on inputs on form does not post them, which is expected and wanted. However, if you prepare a form of 3 objects in a list, disable the first and third, and submit, the 2nd object appears in post header, but does not bind to the list correctly, because it has an index [1] instead of [0].
I understand how model binding works and why it does not bind the posted object that I want, but I don't know how else to describe the problem to get specific results that would lead me to my solution. Anything I search for leads to basic post and binding examples.
List inside the model I'm using:
public IList<_Result> Results { get; set; }
Class _Result has one of the properties:
public string Value { get; set; }
I fill up the list and use it in view like so:
#for (int i = 0; i < Model.Results.Count; i++)
{
...
<td>
<input asp-for="Results[i].Value" disabled />
</td>
...
}
I have checkboxes on form, which remove (with javascript) the "disabled" attribute from the inputs and thus allow them to be posted.
When I fill up the said list with 3 _Result objects, they are shown on form and all have the "disabled" attribute. If I remove the "disabled" attribute from the first two objects and click on submit button, I receive the Results list with first 2 _Result objects, which is as expected.
However, if I remove the "disabled" attribute only from the second _Result object (the first _Result object still has "disabled" attribute), the Results list comes back empty in my Controller method.
In my Form Data Header, I see this: "Results[1].Value: Value that I want posted", which means that post occurs, but list does not bind the object due to the index.
Any idea on how I can achieve that proper binding? Also, the reason I'm using "disabled" attribute is because I'm showing many results on a single page and want to only post those that are selected.
For getting selected items, you could try checkbox with View Model instead of using jquery to control the disable property.
Change ViewModel
public class ModelBindVM
{
public IList<_ResultVM> Results { get; set; }
}
public class _ResultVM
{
public bool IsSelected { get; set; }
public string Value { get; set; }
}
Controller
[HttpGet]
public IActionResult ModelBindTest()
{
ModelBindVM model = new ModelBindVM
{
Results = new List<_ResultVM>() {
new _ResultVM{ Value = "T1" },
new _ResultVM{ Value = "T2" },
new _ResultVM{ Value = "T3" }
}
};
return View(model);
}
[HttpPost]
public IActionResult ModelBindTest(ModelBindVM modelBind)
{
return View();
}
View
<div class="row">
<div class="col-md-4">
<form asp-action="ModelBindTest">
#for (int i = 0; i < Model.Results.Count; i++)
{
<input type="checkbox" asp-for="Results[i].IsSelected" />
<label asp-for="#Model.Results[i].IsSelected">#Model.Results[i].Value</label>
<input type="hidden" asp-for="#Model.Results[i].Value" />
}
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
<div class="form-group">
<input type="submit" value="Save" class="btn btn-primary" />
</div>
</form>
</div>
</div>

ASP.Net MVC 6 PartialView model binding confusion

Background
We need to submit model with items. For that purpose, we make this complex model:
public class PaymentViewModel
{
public decimal? Payment { get; set; }
public string Description { get; set; }
public List<SplittedPaymentViewModel> SplittedPayment { get; set; } = new List<SplittedPaymentViewModel>();
}
public class SplittedPaymentViewModel
{
public short SplittedPaymentId { get; set; }
public decimal? Payment { get; set; }
public string Description { get; set; }
}
For rendering html, we this two views, one regular: CreatePayment
#model ZevApp.ViewModels.Record.PaymentViewModel
...
<input class="form-control" asp-for="Payment" type="number" />
<input class="form-control" asp-for="Description" />
...
<div class="panel-body" id="SplittedPayments">
#foreach (var spItem in Model.SplittedPayment)
{
#Html.Partial("SplittedPaymentPartial", spItem);
}
...
</div>
And the other Partial: SplittedPaymentPartial
#model ZevApp.ViewModels.Record.SplittedPaymentViewModel
...
<input class="form-control" asp-for="Payment" type="number" />
<input class="form-control" asp-for="Description" />
...
As you can see, from the first view, we call partial view and pass them item by item form the SplittedPayment list.
Unexpectedly behavior
We run the code but unexpectedly behavior is occur:
Each partial view bind Payment and Description form parent PaymentViewModel, not from a passed item?
Does anybody know what is wrong?
Each view define model at the beginning of the file.
From the controller we return PaymentViewModel, and for a test, there are tree SplittedPaymentViewModels. But we can't see values from the items.
I found that problem was CreatePayment.cshtml (thanks to the people from MVC community). It doesn't provide any information about the spItem expression when invoking the partial view.
var savePrefix = ViewData.TemplateInfo.HtmlFieldPrefix;
for (var i = 0; i < Model.SplittedPayment.Count; i++)
{
ViewData.TemplateInfo.HtmlFieldPrefix = Html.NameFor(m => m.SplittedPayment[i]);
var spItem = Model.SplittedPayment[i];
#Html.Partial("SplittedPaymentPartial", spItem);
ViewData.TemplateInfo.HtmlFieldPrefix = savePrefix;
}
You can find full description on https://github.com/aspnet/Mvc/issues/4106

MVC3: button to send both form (model) values and an extra parameter

In an MVC3 project, i use an Html.BeginForm to post some (model-)values. Along with those i want to send an extra parameter that is not part of the form (the model) but in the ViewBag. Now, when i use a Button (code in answer here: MVC3 razor Error in creating HtmlButtonExtension), all the form values are posted but the extra parameter remains null. When i use an ActionLink, the parameter is posted but the form values are not :) Any know how i can combine the two? Thanks!
#Html.Button("Generate!", new { id = ViewBag.ProjectID })
#Html.ActionLink("Generate!", "Post", new { id = #ViewBag.ProjectID })
My advice would be to declare a new Object in your App.Domain.Model something like this
namespace App.Domain.Model
{
public class CustomEntity
{
public Project projectEntity { get; set; }
public int variableUsed { get; set; }
}
}
In your view you can acces them easily by using CustomEntity.projectEntity and CustomEntity.variableUsed.
Hope it helps
You can do something like below.
View code
#using (Html.BeginForm("ActionName", "ControllerName", FormMethod.Post, new { #id = "frmId", #name = "frmId" }))
{
#*You have to define input as a type button not as a sumit. you also need to define hidden variable for the extra value.*#
<input type="hidden" name="hndExtraParameter" id="hndExtraParameter" />
<input value="Submit" type="button" id="btnSubmit" onclick="UpdateHiddenValue()" />
}
<script type="text/javascript">
function ValidateUser() {
$("#hndExtraParameter").val('Assignvaluehere');
$("#frmId").submit();
}
</script>
Controller Code
[HttpPost]
public ActionResult ActionName(Model model, string hndExtraParameter)
{
//Do your operation here.
}

MVC3 RemoteAttribute and muliple submit buttons

I have discovered what appears to be a bug using MVC 3 with the RemoteAttibute and the ActionNameSelectorAttribute.
I have implemented a solution to support multiple submit buttons on the same view similar to this post: http://blog.ashmind.com/2010/03/15/multiple-submit-buttons-with-asp-net-mvc-final-solution/
The solution works however, when I introduce the RemoteAttribute in my model, the controllerContext.RequestContext.HttpContext.Request no longer contains any of my submit buttons which causes the the "multi-submit-button" solution to fail.
Has anyone else experienced this scenario?
I know this is not a direct answer to your question, but I would propose an alternative solution to the multiple submit-buttons using clientside JQuery and markup instead:
Javascript
<script type="text/javascript">
$(document).ready(function () {
$("input[type=submit][data-action]").click(function (e) {
var $this = $(this);
var form = $this.parents("form");
var action = $this.attr('data-action');
var controller = $this.attr('data-controller');
form.attr('action', "/" + controller + "/" + action);
form.submit();
e.preventDefault();
});
});
</script>
Html
#using (Html.BeginForm())
{
<input type="text" name="name" id="name" />
<input type="submit" value="Save draft" data-action="SaveDraft" data-controller="Home" />
<input type="submit" value="Publish" data-action="Publish" data-controller="Home" />
}
It might not be as elegant as a code-solution, but it offers somewhat less hassle in that the only thing that actually changes is the action-attribute of the form when a submitbutton is clicked.
Basically what it does is that whenever a submit-button with the attribute data-action set is clicked, it replaces its parent forms action-attribute with a combination of the attributes data-controller and data-action on the clicked button, and then fires the submit-event of the form.
Of course, this particular example is poorly generic and it will always create /Controller/Action url, but this could easily be extended with some more logic in the click-action.
Just a tip :)
i'm not sure that its a bug in mvc 3 as it's not something that you were expecting. the RemoteAttribute causes javascript to intercept and validate the form with an ajax post. to do that, the form post is probably canceled, and when the validation is complete, the form's submit event is probably called directly, rather than using the actual button clicked. i can see where that would be problematic in your scenario, but it makes sense. my suggestion, either don't use the RemoteAttributeand validate things yourself, or don't have multiple form actions.
The problem manifests itself when the RemoteAttribute is used on a model in a view where mutliple submit buttons are used. Regardless of what "multi-button" solution you use, the POST no longer contains any submit inputs.
I managed to solve the problem with a few tweeks to the ActionMethodSelectorAttribute and the addition of a hidden view field and some javascript to help wire up the pieces.
ViewModel
public class NomineeViewModel
{
[Remote("UserAlreadyRegistered", "Nominee", AdditionalFields="Version", ErrorMessage="This Username is already registered with the agency.")]
public string UserName { get; set; }
public int Version {get; set;}
public string SubmitButtonName{ get; set; }
}
ActionMethodSelectorAttribute
public class OnlyIfPostedFromButtonAttribute : ActionMethodSelectorAttribute
{
public String SubmitButton { get; set; }
public String ViewModelSubmitButton { get; set; }
public override Boolean IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
{
var buttonName = controllerContext.HttpContext.Request[SubmitButton];
if (buttonName == null)
{
//This is neccessary to support the RemoteAttribute that appears to intercepted the form post
//and removes the submit button from the Request (normally detected in the code above)
var viewModelSubmitButton = controllerContext.HttpContext.Request[ViewModelSubmitButton];
if ((viewModelSubmitButton == null) || (viewModelSubmitButton != SubmitButton))
return false;
}
// Modify the requested action to the name of the method the attribute is attached to
controllerContext.RouteData.Values["action"] = methodInfo.Name;
return true;
}
}
View
<script type="text/javascript" language="javascript">
$(function () {
$("input[type=submit][data-action]").click(function (e) {
var action = $(this).attr('data-action');
$("#SubmitButtonName").val(action);
});
});
</script>
<% using (Html.BeginForm())
{%>
<p>
<%= Html.LabelFor(m => m.UserName)%>
<%= Html.DisplayFor(m => m.UserName)%>
</p>
<input type="submit" name="editNominee" value="Edit" data-action="editNominee" />
<input type="submit" name="sendActivationEmail" value="SendActivationEmail" data-action="sendActivationEmail" />
<%=Html.HiddenFor(m=>m.SubmitButtonName) %>
<% } %>
Controller
[AcceptVerbs(HttpVerbs.Post)]
[ActionName("Details")]
[OnlyIfPostedFromButton(SubmitButton = "editNominee", ViewModelSubmitButton = "SubmitButtonName")]
public ActionResult DetailsEditNominee(NomineeViewModel nom)
{
return RedirectToAction("Edit", "Nominee", new { id = nom.UserName });
}
[AcceptVerbs(HttpVerbs.Post)]
[ActionName("Details")]
[OnlyIfPostedFromButton(SubmitButton = "sendActivationEmail", ViewModelSubmitButton = "SubmitButtonName")]
public ActionResult DetailsSendActivationEmail(NomineeViewModel nom)
{
return RedirectToAction("SendActivationEmail", "Nominee", new { id = nom.UserName });
}
[OutputCache(Location = OutputCacheLocation.None, NoStore = true)]
public ActionResult UserAlreadyRegistered(string UserName, int Version)
{
//Only validate this property for new records (i.e. Version != zero)
return Version != 0 ? Json(true, JsonRequestBehavior.AllowGet)
: Json(! nomineeService.UserNameAlreadyRegistered(CurrentLogonDetails.TaxAgentId, UserName), JsonRequestBehavior.AllowGet);
}
I encountered the same issue.
I also attached an on submit event to prepare the form before submit. Interestingly, when I insert a break point in the on submit function, and then continue, the problem has disappeared.
I ended up with an Ajax form by removing the Remote attribute and validate the field using the ModelState.

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