I'm new to Ajax, but I think I know how to reasonably use MVC + model binding.
What I'm trying to do is to create an Add button (or Ajax.ActionLink) to add a new row in my grid for data entry. Example: Think of a typical Order entry system with Order (header) and Product (items). My OrderViewModel contains an "Order" object, and the Order object contains a collection List.
The way I plan to do this is that my View render the grid in a PartialView, and the PartialView is a simple for-loop to create the table tags from the List. I will use the default model binder (for collections).
Anyone have suggestions on how to do this?
I've already figured out how to do this using jQuery, but I want (i think I want) to try and use Ajax so that I can add my custom business logic (e.g. like setting defaults, translations, etc.)as opposed to do this client-side.
In other words, I want to do do something similar to what the Telerik grid does with its Ajax Editing with the Add/Remove link/buttons.
Tips and sample code would be greatly appreciated.
One of my challenges, and not sure if I'm going down the wrong way, is that I don't know how to pass back the model back to the Controller Action from the Ajax submit. When I look at Telerik's code, it looks like they store the persisted items in HttpContext.Session, and this is exactly the reason why I don't want to use their grid.
Thanks.
They might choose the session repository storage for demonstration purposes. If you transform the logic from their SessionProductRepository class for your model and implement identical Update/Insert/Delete methods for it, you'll probably get what you want.
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I need to get dynamically a list of Web Controls from View to be used in the model(dropdownlists, inputs, checkboxes, ...). Is it possible? I generate the controls in Razor.
My application should store last values of all controls for each user into the database and use them as predefined values for the next call of the form.
Any advice would be appreciated.
I need to get dynamically a list of Web Controls from View to be used in the model
First of all, you're probably going to find MVC a lot easier to understand if you abandon terms like "web controls" and the like. Your view, which may not may not be utilizing helpers to do so, is simply building HTML. Nothing more.
But more to the point, what you're proposing is exactly the opposite of what MVC does. Your model should have no knowledge of the structure of the view. (inputs, selects, other form elements, etc.) The model contains the data and business logic necessary to render the view. The view then uses that data and logic to build its interface.
You can post the values from the resulting HTML form to a server-side action. Then from that action you can store those values in a database or do whatever you like with them. If the key/value pairs of those values can logically be structured into the form of a model then the action can accept that model as a parameter, if not then it can also just as easily accept parameters for each individual value. (Though if you find yourself using a lot of parameters it would be better to build a simple view model just to encapsulate them.)
The order of operations is something like:
A request is made to a controller action.
That controller action invokes logic on a model and provides that model to a view.
The view binds its UI elements to the model's data and renders the interface.
The user interacts with the interface and uses it to perform a request to another controller action.
That controller action receives the data from that request, performs server-side logic, etc.
and so on...
My website is built around tabs. I have one single page with multiple partial views that display each tab.
The problem im facing now is I want to loop through files that the user has uploaded and display them in one of my partial views. This requires me to send the file list as a paramater in my action like this:
//Uploadedfiles is a function that adds the files to a list.
var files = UploadedFiles();
return View(files);
Because im only using one view to display all my partial views, i get:
The model item passed into the dictionary is of type 'Microsoft.WindowsAzure.Storage.Core.Util.CommonUtility+d__0`1[Delamapp.CloudStorageServices.UploadEntity]', but this dictionary requires a model item of type 'Delamapp.Models.LoginFolder'.
This means im required to not send a model item to my index view. Now, the only thing i can think off is adding my file list to viewbag and then display them on my view. BUT.. The files require high security. How safe is viewbag? Can you for example store sensitive login information in there? Can you think off some other way to accomplish this?
Thank you in advance
You can pass a model item to your view, but the model item you are passing doesn't match the type of model that your view uses (that's what the error message says).
So you need to do one of the following:
Modify your view to accept the model type that you are passing to it
Put the data you want to pass into the model type that your view is expecting
Create a new model type for both your data and for the view, and use that
In terms of security, I don't think using a view bag versus model binding really enters into the question of security. Both are just ways of passing data in between the controller and the view, and that all takes place within the ASP.NET process (perhaps you have ViewBag confused with Web Forms' ViewState?).
The problem is that a have to show dynamically the fields on the web page using MVC and Razor VE depending on the user permissions from the database. Thus, every user has its form and field mappings setup and depending on it I have to show/hide the fields on the form. So, I am thinking of the best applicable approach to implement such a behavior.....
Any ideas would be very much appreciated!
If you would like to pass dynamic object use ViewBag, but in my option normal model is better options. For hiding and showing different section: did you think about partial views and render it were are they need? You can pass to it "properties" of your model.
The well described model of View/Controller/Model is quite clear when it comes to object (say a book) update/delete/save etc...but how do you guys organize the common code such as populating drop down lists (from db)?
I use Jquery ajax to call control's action, but in cases such as getting the arrays for drop down lists, I feel like these should not reside in the same BookController .
Can I have a Controller without the matching view for these purposes only?
Thank you
Each ViewModel is data for a View to render. It sounds like you understand that. When Ajax calls for Data, I think it makes more sense for the controller for the view be responsible for creating another ViewModel and returning it as Json for the rendered view. If mutliple views need to retrieve a list of Books, should call /Books/AjaxList (bad method name example), just like any view under /Books. Seperating the responsibility of creating a ViewModel based on Ajax or not Ajax doesn't make sense to me.
I am wondering if there is a way to make ASP.NET controls play nicely with my ASP.NET MVC app. Here is what I am doing.
I have an order page which displays info about a single Order object. The page will normally have a bunch of rows of data, each row representing an OrderItem object. Each row is an ASP.NET User Control. On the user control there is a form element with two text boxes (Quantity and Price), and an update button.
When I click the update button, I expect the form to post the data for that individual OrderItem row to a controller method and update the OrderItem record in the database.
Here is my problem: When the post happens, the framework complains because the fields on the form don't match the parameters on the controller method. Each form field is something like "OrderItem_1$Quantity" or "OrderItem_2$Price" instead of just "Quantity" or "Price" which would match my method parameters.
I have been told that I can overcome this by making sure that the IDs of all my controls are unique for the page, but allow the NAMEs to be repeated between different forms, so that if a form for an individual row is posted, the name can be something that will match what is on my controller method.
The only problem is that I am using ASP.NET controls for my text boxes (which I REALLY want to continue doing) and I can't find any way to override the name field. There is no Name propery on an ASP.NET control, and even when I try to set it using the Attributes accessor property by saying "control.Attributes["Name"] = "Price";" it just adds another name= attribute to the HTML tag which doesn't work.
Does any one know how I can make this work? I really don't like all of the HtmlHelper functions like TextBox and DropDown because I hate having my .aspx be so PHP or ASP like with the <%%> tags and everything. Thanks!
I think you're straddled between two worlds of ASP.NET WebForms and ASP.NET MVC. You really need to use the Html.TextBox methods, etc. in MVC. This gives you complete control over the markup, which is one of the main benefits of MVC.
The very problem you're having with control over the generated HTML, e.g. getting two name attributes, is exactly what MVC is designed to address. If you stop fighting it and go with the flow, it'll work much better.
<% %> tags aren't a problem unless you have logic in there. Putting simple presentation logic on your view is fine.
If you don't like this, then maybe it's better to stick with standard ASP.NET.