I have three classes - Employee, Project and TrainingProgram. Then I have a fourth class, TrainingRecord which consists of an Employee, the Project they trained for, the TrainingProgram they completed and the date they completed it on.
Users can create new TrainingRecords from two spots - either through an Employee (they select the Project and TrainingProgram, then submit) or through a Project (they select an Employee and a Training Program, then submit).
When inside the Create page for TrainingRecord, what's the best way to tell which parent I came from (the details page of an Employee or the details page of a Project) and how would I redirect the page back to that parent after the new TrainingProgram is submitted?
You could pass a returnUrl parameter to the controller action which indicates where to redirect to in case of success.
I would've used session variables but you could use querystring as well.
Related
I apologize if this is a newb question. I'm more experienced with Windows forms and just getting started with MVC. I have a class called PackagedProduct which consists of a Package and a Product that are selected via drop down list and represented by their own models.
PackagedProduct
Sometimes though, the Product may not exist yet so I have an ActionLink that directs to the Create action of Product.
#Html.ActionLink("Create New Product", "Create", "Products");
Product
How can I allow the user to create the new Product, but when the create button is pressed to return to the PackagedProduct view where it originated with the existing data still populated(in this case UPCCode and Package)? The PackagedProduct won't have been created yet because it is missing required data until the correct Product is created so I can't just pass back the PackagedProductID. Thoughts?
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
We are beginning the process of moving from Web Forms to MVC for all of our new applications. I am working on porting our Master Page over and am trying to satisfy the requirements that we need a single master page to be used by all applications. The primary navigation for the application needs to be in a menu within the master page. Accomplishing this was easy, the hard part is that each application may need to determine what to display in the menu using a unique set of rules. Some apps can simply say, here's the menu structure to use via something like a SiteMap. Others need to determine what is displayed in the menu based on what roles the user has, this can also be handled easily with a SiteMap. The situation that I'm struggling with is that some apps need to generate the menus based on the roles the user has, but also on the data on which they are working. i.e. The same user may have different option in the menu for a page if they are working on object 'foo' than they do if working on object 'bar'.
What I've done at this point, is I've created an HtmlHelper that is called by the master page view and takes a list of objects of a custom type and returns an unordered list that is styled by a jQuery plugin to display the menu. The list of objects the helper method takes are passed to the view using the ViewData dictionary. Currently, the value of this ViewData node is set within the constructor of each controller. This allows each page, and potentially each method, to set a different menu without having to set the value in each action method, unless its needed. I have also created a class that parses a SiteMap and returns the list of items needed to build the menu. This class is what I'm using to set the ViewData value in the controller. The idea being that if an application needed more control of how the menu data was generated, they could create their own class to generate the data as long as it returns a list of the correct type of objects.
This solution seems to work fine so far, it just doesn't 'feel' right for some reason. I'm hoping that I can either get some ideas of better way to do this or some reassurance that this is a valid approach to solving this problem.
If it is something that will be on every page, do something like this:
Create a base controller:
public class MyBaseController : Controller
Have this controller get the data it needs and send that data in the ViewData["menu"] to the View. Then have all your controllers inherit from this one:
public class HomeController : MyBaseController
In the Master Page, loop through your ViewData and create your menu.
(I did something like this for my sub-menu which displayed a list of categories.)
In the book I am reading (Pro ASP.NET MVC Framework by Apress) they use Html.RenderAction for the menu in the masterpage. I am a Asp.net MVC novice so maybe somebody else can give more info about this.
You can download the sourcecode at apress.com though so maybe that could help.
Let say I am rendering list of products with Add To Cart link / button next to each.
I also have a CartController with AddToCart Action that accept a parameter of Product type.
After product is added to cart user should stay on the same page (Product list) - not to be redirected to Cart or something.
I am rendering Cart summary partial view that should update itself.
So my question is about implementation of the Add To Cart link / button.
Should I use: Html.ActionLink(...)
or Html.BeginForm() and Submit button.
Maybe there is other ways...
How do I send Product info in each case?
Thanks
I suggest using a jQuery.post() request to your CartController.AddToCart. Make AddToCart a partial view. And then show a modal popup (div on top of your page) that shows that the product was added to the cart...then do a fade out!
Keep it simple.
Now keep in mind that some of your users won't be able to support jquery/javascript. So make the initial add to cart button post to an add to cart page (not partial page..full page)...which can return them to the original page. Then spot weld your jquery function on top of the add to cart button. This way you cover both worlds nicely.
Take a look at the concept of unobtrusive javascript/jquery.
The way I do it is to have a form for each add button (with maybe the quantity also), since you want your AddToCart action only receive POST actions anyway, that way you process all the add to cart logic and then redirect to your main catalog view (or something like that :)
Again I'd take into consideration what happens if the user doesn't have javascript. It's not very likely these days, but do you want to lose a sale just because someone accidently turned off javascript?
So what I'd do is create the somewhat typical AddToCart link (<a class="add" href="/Shop/AddToCart/5">). The AddToCart controller would then do it's stuff and redirect back to the product listing page (you might have to pass a parameter to specify which page to go back to).
So that's the first step to consider -- javascript turned off. Now you can think about how to do it with javascript.
Capture the click event ( $('a.add').click(...) ) and then you can do two things. One would be to call the URL (you can get it out of the event object) and then separately update the cart. You can also add a parameter to the URL so that it displays the cart partial view, doing something like (written from memory):
$('a.add').click(function(event) { $('#cart').load(event.target.attr('href') + '&showcart=1');
James
I have a View class (OrderView.aspx) which shows the details of an order (Account Name, Order Date) as well as a list of order lines via the Repeater control. Each order line is represented by a User Control View (OrderLineView.ascx) which shows the details of the order line (Item Name, Quantity, Price). I have a model object called Order which I use as the data source for all of this, which I pass as the model object for the view.
Each OrderLineView user control has a Save and a Delete button. I have the Save button posting the contents of a form within the OrderLine control to a Save method on the Controller and then RedirectToAction back to the same Order page (this refreshes the whole page, nothing AJAXy about it). I have the Delete button linking to a method on the Controller that tries to delete, and then RedirectToAction back to the same Order page. If the delete fails, however, I want a little error message to show up next to the delete button when the page renders again(remember, there is a delete button for every order line on the page, so I only want the message next to the one I clicked). My questions:
1 - How do I pass this data from my Controller method to the specific User Control? Should I somehow add it in to the model? Seems like a bad idea (since it really isn't part of the model).
2 - Should I have a OrderLineController for the OrderLine operations as well as a OrderController for Order operations? I just want to know if best practice is to have a separate Controller for every view.
3 - I have seen how some people might call RedirectToAction with an anonymous type value like this:
RedirectToAction("ViewOrder", new { Id = 1234, Message = "blabla"});
but this makes the Message value show up in the URL string. I am OK with that, but would prefer that it doesn't show if possible.
4 - Also, for accessing properties of the Model from within the view, I find myself doing this all of the time:
foo(((someModelType) this.ViewData.Model).SomeProperty);
I don't like this for a number of reasons, one of which is the fact that I don't want my view to be coupled with the type of my model (which is why I am using ViewPage instead of ViewPage). I would much prefer to be able to have a call like this:
foo(ModelEval("SomeProperty"));
Is there such a thing? I have written my own, but would like it if I didn't have to.
1
Check out ModelState.
ViewData.ModelState.AddModelError("something.Name", "Please enter a valid Name");
ModelState is actually a dictionary, so you could identify the errors on a per-control basis. I don't know if this is a best practice, but it would probably work.
Try something along the lines of
ViewData.ModelState.AddModelError("something#3.Name", "Please enter a valid Name");
and in your view, you could put
<%= Html.ValidationMessage(string.format({"something{0}.Name", YourUniqueId))%>
4
You can strongly type your view, so you don't need that cast, but if you're concerned about tightly coupling, this may put you off. But having the strong type there is no more tightly coupled than having a magic string point to that property of the model anyway. The former just gives you type safety and the glory that is intellisense.
Since your OrderLine has a unique ID you can use that to construct a key to be placed in the ModelState errors container.
public ActionResult Delete(int? Id)
{
ModelState.AddModelError("OrderLine" + Id.Value, "Error deleting OrderLine# " + Id.Value);
...
}
and then use the ValidatinoMessage helper. This will check the ModelState to see if an error exists and if it does it will display the message. Otherwise it's blank.
<%= Html.ValidationMessage ("OrderLine" + Id)%>
In the next release of MVC Model will become a top level property so the following
foo(((someModelType) this.ViewData.Model).SomeProperty);
can be written as
foo(Model.SomeProperty);
Model objects should already be typed unless you're using public object as a property?