In my MVC application for booking accommodation I have the following:
Action to display the selected room with input-forms for extra info GET:"Details"
This view has multiple forms on it, each posting to a different action.
Examples:
Action to update the number of guests POST:"UpdateGuests"
Action to select start date POST:"SelectStartDate"
Action to add breakfast POST:"AddBreakfast"
Action to delete room POST:"RemoveProductFromCart"
Action to proceed to next step POST:"Proceed"
Most of these actions will redirect back to the GET:"Details" view so the user can perform another action if required, in the case of the proceed, this will redirect to the next view OR if there is some reason they cannot proceed it will display the validation message as to why on the "Details" view.
I'm not sure of the best way to deal with validation, here's some options I've thought of.
use TempData[] to store validation messages and REDIRECT to "Details" view where we add any TempData errors so the ModelState.
in the POST:"xxxxxx" Action populate the ModelState and RENDER the "Details"
This is not a high volume site so TempData is an option.
Any ideas gratefully welcomed.
Edit:
Additional info:
I'm using DataAnnotations for validation rules in some places.
adding Ajax as progressive enhancement is planned, but it should work without.
I think that your second option is the best : each post actions will do the required validations, populate the ModelState with the error messages and every post will return the same view, rebuilt using your model.
Another option, a little bit harder but giving a much better user experience is to do some actions (like update number of people, select start date, add breakfast) using an ajax call. That way, you can return only the little bit of informations required by this action, refresh only that part of the screen and add some error messages if needed.
I hope it will help.
Have you taken a look at how nerd Dinner does validation? I've used this approach with forms that contain several Partial Views and it works great.
You can even modify to validate using jQuery on the fly if that's what you want to do.
Related
I'm making the transition from webforms to MVC (I know, 3 years late) and I "get it" for the most part, but there's a few things I'd like advice and clarification on:
First off, what happens if you want to dynamically add inputs to a view? for example, in an old webform for generating invoices I had a button with a server-side click event handler that added an extra 5 invoice item rows. The stateful nature of webforms meant the server handled the POST event "safely" without altering the rest of the page.
In MVC I can't think how I'd do this without using client-side scripting (not a showstopper, but I would like to support clients that don't have scripting enabled).
The second problem relates to the invoices example. If my Model has a List, how should I be generating inputs for it?
I know data binding is a possible solution, but I dint like surrendering control.
Finally, back to the "stateful pages" concept - say I've got a Dashboard page that has a calendar on it (I wrote my own calendar Control class, the control itself is stateless, but can use the webform viewstate to store paging information) - how could a user page through the calendar months? Obviously POST is inappropriate, so it would have to be with GET with a querystring parameter - how can I do this in MVC? (don't say AJAX).
Thanks!
In MVC you design your actions to accommodate your needs. For example, if you wanted to be able to add 5 rows to an invoice NOT using client-side scripting, you'd probably have your GET action for the invoice generation take a nullable int parameter for the number of rows. Store the current number of rows in the view model for the page and generate a link on the page to your GET action that has the parameter value set to 5 more than the current value. The user clicks the link and the GET view generates the page with the requested number of rows.
Controller
[HttpGet]
public ActionResult Invoice( int? rows )
{
rows = rows ?? 5; // probably you'd pull the default from a configuration
...
viewModel.CurrentRows = rows;
return View( viewModel );
}
View
#Html.ActionLink( "Add 5 Lines", "invoice", new { rows = Model.CurrentRows + 5 }, new { #class = "add-rows" } )
You would probably also add some script to the page that intercepts the click handler and does the same thing via the script that your action would do so that in the general case the user doesn't have to do a round trip to the server.
<script type="text/javascript">
$(function() {
$('.add-rows').click( function() {
...add additional inputs to the invoice...
return false; // abort the request
});
});
</script>
Likewise for your calendar. The general idea is you put enough information in your view model to generate all the actions that you want to perform from your view. Construct the links or forms (yes you can have multiple forms!) in your view to do the action. Use parameters to communicate to the controller/action what needs to be done. In the rare case where you need to retain state between actions, say when performing a wizard that takes multiple actions, you can store the information in the session or use TempData (which uses the session).
For things like a calendar you'd need the current date and the current view type (month/day/year). From that you can construct an action that takes you to the next month/day/year. For a paged list you need the current page, the current sort column and direction, the number of items per page, and the number of pages. Using this information you can construct your paging links that call back to actions expecting those parameters which simply do the right thing for the parameters with which they are called.
Lastly, don't fear AJAX, embrace it. It's not always appropriate (you can't upload files with it, for example), but your users will appreciate an AJAX-enabled interface.
In MVC you can store application state in various ways. In your controller you have direct access to the Session object and you can also store state to the database.
your view can contain basic control flow logic, so, if your model has a list you can iterate over it in the view and, for example, render an input control for each item in the list. you could also set a variable in a model to be the maximum number of rows on the viewpage and then render a row in a table for the number specified by the model.
paging is basically the same thing. you can create a partial view (user control in the webform world) that shows page numbers as links, where each link calls an action that fetches the data for that page of results.
i'm not sure what your beef is with ajax or javascript
I have a Product edit screen. The user can select a Vendor for the Product. To do this, I display a jQueryUI dialog box which allows them to browse for and select a Vendor. When the user selects the Vendor, I update a hidden VendorID input on the page, which is part of my page's model. I also update several divs with details about the Vendor they have selected. These are for display purposes only--only the id is needed to persist the selected Vendor.
This all works fine and dandy except when there is an error on postback, in which case I redisplay the same view. ModelState takes care of preserving all my form fields (including the hidden VendorID). However, my divs with the Vendor text are (of course) empty since they're not posted to the server.
I first went down the path of creating hidden fields for each of my Vendor display fields and putting them on the model. Then the hidden fields survive the postback, but that doesn't solve the problem of actually redisplaying the text on the screen.
The three options I can think of are:
On postback, if there is an error, go to the database, fetch the Vendor using the supplied VendorID and re-populate the model with the text I want to display.
Use RenderAction and have an action which renders the details of the selected Vendor.
Use readonly textboxes instead of divs to display the Vendor details.
None of these feel very satisfactory to me. I feel like I might be missing an obvious solution. Are there any better solutions?
I would suggest you not have the extra Vendor information come down as part of the main page. Create a javascript function showVendorInfo(). When called, if the VendorID hidden input has a value, it gets the relevant Vendor information via AJAX and displays it, using an AjaxGetVendorInfo action method. Call this function from two places:
In document.ready()
after a Vendor is selected with jQueryUI display.
Now, this would be in an action method. You could, if you expect your users to have latency issues, do the following to avoid some ajax calls: In the view check if you know the VendorID; if so, call Html.RenderAction call the same AjaxGetVendorInfo action method from the view.
A bonus to this is that it avoids what I have found to be a big no-no: Including both display-only values and model-binding values in your ViewModel. This makes for a very confusing ViewModel, especially when there are validation errors. [Getting on soap box] It's best to have your ViewModel to just have properties intended for modelbinding, for your state. Put list values, extra display information, etc., into ViewData or have them show up via AJAX.
I have an asp.mvc app the presents to the user different forms when they click on the next button - like a wizard. I do it this way so I can use JQuery to validate each form as the user progresses through them. i.e.
...
// use jquery validator to funk up the form validation
// user clicks the Next button ...
switch(currPageIndex) {
case 0:
if($('#form1'.valid()) {
$('#form1').hide();
$('#form2').show();
}
break;
}
...
However I can't use a single submit button to post the all the forms formcollection data back to my controller - if I do I only get back the one form that the submit button was in and not all of them.
Is there some magic icantation I can type in to get all the forms data sent back to the controller?
Presumably I can cruft up the data myself and send it back to my controller as a jason string, but I'm not sure if this is the best way.
Many thanks.
Wizard-like forms basically rely on a model which is kept on the server-side (in session or a database table) and kept updated.
For example, each post from the client you get back the model from session or database and then call UpdateModel() using the FormCollection which updates the model and the you can check if it is valid.
You can only submit one form at a time, however there are multiple ways around this in your scenario. When you change to the second form you could populate some hidden fields using javascript that would contain the information from the previous form. Then it would all be in the second form and you wouldn't have a problem getting the information.
You could also do it via ajax/json, but then you would probably want to do it with both of the forms data anyway.
In the end I just json'd up the form data and ajax'd it over to the controller, it works very well, nice and and clean to.
many thanks for the replies.
You can do that using $('#form1').submit() function, I don't think there is another way.
I have a asp.net mvc page which renders a record from a database, it uses RenderPartial to call another view which renders an editable list of items related to that record.
My problem is I want a since save / submit button which not only saves changes made for that record but also changes made in the RenderPartial part... I have created a method accepting POST in the RenderPartials controller but it doesn't get called? Any ideas? Or am I using RenderPartial wrongly? I did it this way so that I have a controller that handles the subset of data
Update:
I don't think I've been clear enough:
Imagine a situation where you have a page that is filled with information from lots of different tables in a database... for example imagine you have a record of a person, and then you have all the links they have to Organisations that you want to list on the page, so the page contains:
Individual Name, Email, etc...
AND
Organisation Link 1
Organisation Link 2, etc... from a link table
Because of the amount of data I want to render of the page, I figured using different controllers to render each part would make sense.. but then when saving the data do I have to use just one controller method or can I call one controller to another... I only have one form and one 'save' button for the whole page
I hope this is clearer?
You don't need to have a specific controller for each controller, although I suspect you meant to say "I have created a method accepting POST in the RenderPartial's action ..."?
When you accept the default html helper commands, it can sometimes get confusing which action will be called. For a particular web page, the tag will determine where to POST values. So the action called will be dependent on the controller/action you specify in your Html.BeginForm call.
For example, here's a form we use from an ascx page:
<% using (Html.BeginForm("InvoiceDetail" //Action
, "CompanyInvoice" //Controller
, FormMethod.Post
, new { #id = "InvoiceForm", #autocomplete = "off" }))
{%>
A form can post to any action, in any controller. Not that you'd want to, but it's quite flexible. You can also have multiple forms in a single web page now, which is great for complex forms.
I've been playing around with the ASP.NET MVC Framework and the one thing that's really confusing me is how I'm meant to do server side validation of posted form data. I presume I don't post back to the same URL, but if I don't, how do I redisplay the form with the entered data and error messages? Also, where should the validation logic go? In the model or the controller? This seems to be one of the few areas where web forms are much stronger (I miss the validation controls).
Here's an overview of the flow in MVC:
/new - render your "New" view containing a form for the user to fill out
User fills out form and it is posted to /create
The post is routed to the Create action on your controller
In your action method, update the model with the data that was posted.
Your Model should validate itself.
Your Controller should read if the model is valid.
If the Model is valid, save it to your db. Redirect to /show to render the show View for your object.
If the Model is invalid, save the form values and error messages in the TempData, and redirect to the New action again. Fill your form fields with the data from TempData and show the error message(s).
The validation frameworks will help you along in this process. Also, I think the ASP.NET MVC team is planning a validation framework for the next preview.
You might want to take a look at ScottGu's latest post for ASP.Net prev 5. It walks through a validation sample that is very interesting:
http://weblogs.asp.net/scottgu/archive/2008/09/02/asp-net-mvc-preview-5-and-form-posting-scenarios.aspx
As far as I can tell everyone is still trying to figure out the "standard" way of doing it. That said definitely check out Phil Haack and Scott Guthrie's latest posts on MVC and you'll find some interesting info on how they did. When I was just playing around with it for myself I created a ModelBinder for the LinqToSql data class that I had generated. You can check out this post to find out how to put together a basic ModelBinder:
ASP.Net MVC Model Binder
The in your action if you had created a "Product" ModelBinder you would just declare the action like so:
public ActionResult New(Product prod)
And the model binder will take care of assigning posted data to the objects properties as long as you've built it right anyway.
After that within your GetValue() method you can implement whatever validation you want, whether using exception's, regex's, or whatever you can make a call like:
(ModelStateDictionary_name).AddModelError("form_element_id", "entered_value", "error_message");
Then you can just throw a <%= Html.ValidationSummary() %> in your view to display all your errors.
For client-side validation I just used jQuery. After you get a basic sample set up though you can start doing some interesting things combining all that with Partial Views and Ajax calls.
Have you taken a look at this?
http://www.codeplex.com/MvcValidatorToolkit
Quoted from the page
The Validator Toolkit provides a set
of validators for the new ASP.NET MVC
framework to validate HTML forms on
the client and server-side using
validation sets.
I'm afraid that someone more MVC-savvy than me would have to speak to where in the architecture you should put things.
I'm just learning the MVC framework too so I'm not sure how off this is, but from what I understand you would have a form on a View such as Edit.aspx. This form would then post to the controller to another action method such as Update() passing in the contents of the form that you set in Edit.aspx as parameters.
Update(int id, string name, string foo)
You could do the validation within that method. If all is ok,
return View("Item", yourObject)
There is Castle.Components.Validator module in Castle project. It's very agile and powerfull. It generates validation rules based on model attributes (or any other source) and even able to generate JS validation using jQuery, Prototype Validation, fValidate and other.
Of course it's wise to abstract validator away behind IValidationEngine interface.