In the application I'm developing in ASP MVC 3 I have the following scenario. I have some properties of the model that I wanna use after the page makes a request, however when the post request is done they arrive as null since they are not bound to any control in the view form.
For what I've read this is the expected behaviour of ASP MVC and people recommend to use a #Html.HiddenFor() to be able to receive them, but I don't want this information to be available to user in case he selects "View source" from the browser.
In JSF I remember that you could use the #ViewScope annotation for this scenario, but is there something similar in ASP MVC? For what I've read saving them in the ViewData property will not work either and I do not want to use the Session because this properties will only be relevant in this particular view.
If I understand your question correctly, you may be looking for something like TempData.
You can read about it here:
http://blogs.teamb.com/craigstuntz/2009/01/23/37947/
A more recent post can be found here:
http://codeoverload.wordpress.com/2011/05/29/controller-tempdata-in-asp-net-mvc-3/
Related
I am currently working with integrating a classic asp site with MVC3. I have some questions on some areas of the integration that I would like some feedback on.
Firstly, I have a asp page posting to an MVC controller action. I have very little scope to modify the asp page. I want to take the form fields posted from the asp page and map them in to a model object. The posted values have obscure names such as "my_name" which I want to map to Name property on the model object. Is the best way of doing this via a Model Binder or is there an alternative?
Next question I have is a follow on from the previous, I am concerned with any cross site scripting so want to check the values of the posted variables to be valid and contain no strange characters etc. Is there something built in to MVC3 that does this out of the box?
When the asp page posts to the controller action, I would like to show a waiting icon while the controller action is processing as the controller action could take 10 seconds plus as it must call external systems etc. Therefore I don't want the post to seem as its hanging. Is it possible to wire up the controller action to return a view with a waiting icon, while the main body of the action is processing in the background and once complete redirects to another page?
Is the best way of doing this via a Model Binder or is there an
alternative?
The best way of doing is a model binder. You can have a custom model binder to take care of the ASP scenario that maps the my_name to Name. Mostly you should have a separate action to handle the requests coming from classic asp and you can link the custom model binder to only this action.
Is there something built in to MVC3 that does this out of the box?
The request validation is enabled as default in MVC. So if an user tries to post a script block to the action MVC will throw exception. Of course you can switch off request validation by decorating the action with ValidateInput(false) if you need.
For long running actions you have to use asynccontrollers.
I need to port the functionality of this one and only one AJAX control to MVC, but given the poor selection of MVC controls out there, I think I need to bring this legacy control into the MVC world...
I'd rather not taint my MVC project with ASP.NET controls, and welcome json/MVC alternatives you know of. (post them if you know of any)
Sample UI that I need in ASP.NET MVC
Back to porting
Although it's unfortunate that I am left to porting this control to MVC, it seems to be a widely accepted practice since Telerik has detailed instructions on how do this.
That makes me ask:
How common is it for a MVC website to use ASP.NET controls?
Again I'll mention I don't want to do this so I welcome MVC-specific alternatives. That being said, I'll proceed with trying to merge that control with my existing site. </End Disclaimer>
If you click on this hyperlink, and look at the source code at the bottom, can you tell me where I should put the following in MVC?
Code behind (My first instinct is to use a Controller but another SO question indicates I should create a create a ViewName.aspx.cs file)
How do I port the SQLDataSource to the new "Model" way of thinking. I know they are different in nature but I don't know how to present data to a ASP.NET control in a way that it will consume the information.
How do I handle the AJAX component? This control has an AJAX component using callbacks. Yes this is getting ugly, but it seems like I have to do this.
Apparently this model saves data in session or view-state. I have no idea if this even work in MVC. Guidance, an alternate control, or a life preserver is much appreciated.
I've already done research and have instructions from Telerik here and here that describes how to get started with placing a simple menu, but I need a little assistance with the more complex controls like this one.
Note: For all the commentary that has hit this question, please remember that I only want this one ASP.NET control functionality; I can't find a comparable control in MVC.
porting from asp.net webforms to MVC is a paradigm shift.
Directly porting does not work.
The Model is where you typically describe your data and do the data access
the View is for displaying the data
The controller plums the other two together
So SQLDataSource is your data access layer and would therefore go to your model
the problem with the thought pattern of SQLDataSource == Model then you get away from the point of decoupling your presentation from data access
You have to think of MVC development as a new build
I would pick a book or video series from your preferred source and learn starting with MVC3 (it has some differences that simplify build speed and reinforce the difference between webforms and mvc)
Hope this helps.
This article explains how to run web forms and mvc together
http://weblogs.asp.net/rajbk/archive/2010/05/11/running-asp-net-webforms-and-asp-net-mvc-side-by-side.aspx
This is by telerik and explains the limitiation of the grid and what is need to get it to run.
http://blogs.telerik.com/aspnetmvcteam/posts/08-11-06/asp_net_ajax_controls_in_asp_net_mvc.aspx
Add an IFrame in your MVC view that just shows the WebForms page (or just use that control on a single WebForms page).
There is nothing that says you can't have a site with both WebForms and MVC pages. You can route a single URL to a WebForm just for this control.
Why not just use the telerik MVC controls? They work quite well. Either get them via a NuGet package or visit this link http://www.telerik.com/products/aspnet-mvc.aspx
I would rather use ViewModel instead of code behind
You don't have to throw away SqlDataSource you can use result set and buld from it your model, problem may be column names in result set... tricky but can be done
Since there is no components in MVC except helpers youll need help of jQuery probably, it easy
$.ajax({
url : "/controller/action",
data: { /*json or serialized form */ },
successs: function(data){
//if you got response as html from /controller/action
$("#some_div").html(data);
}
}
Session is available in MVC but viewstate not, you can use HttpContenxt.Cache or TempData if you need something like viewstate. USe TempData to keep data between redirections, or httpcontext.cache to cache your data further more.
I can't find similar functionality in an MVC control
MVC doesn't really have a concept of controls in the same way that ASP.Net does - there are only really the plain old HTML controls (i.e. hidden input, text input, checkbox, radiobuttons, select box, text area, password and buttons).
When you need something more complicated than the plain HTML Controls you need to use some JavaScript to achieve this.
I'm not sure that you will be able to 'port' the control into MVC - you will most likely have to try and re-create it your self using an MVC controller and a partial view with a fair bit of a javascript to create the control.
Have a look at the JQuery UI Autosomplete plugin - you could probably use this to acheive something similar
I am learning ASP.NET MVC, and ran across a video on the asp.net/mvc website that showed how to retrieve a value from a textbox after a postback. In the video the author simply grabs the value from the Request object in the controller.
It seems like this breaks the separation of concerns concept? By doing this the controller is now dependent upon the presence of a Request object which won't exist if one runs unit tests against the controller.
So I assume this is an incorrect way of retrieving form data on a postback. What is the correct way? Once I am in my controller, how do I get access to the postback data?
It seems there should be some intermediate step that essentially pulls the data from the postback and packages it into a nice object or some other format that the controller would then used?
The data should be posted back to your Model or ViewModel. Your controller method that handles the POST will expect the model to be provided as a parameter.
Here is a blog entry that gives an example
Using model binding, MVC can populate data coming from the form data, the query sting, cookies, and a number of other sources directly into your object model or other paramters defined as parameters to your action methods in the controller.
There's too many details of how this works to summarize here, but it is the cornerstone of the power of ASP.NET MVC.
Check out Models and Validation in ASP.NET MVC as a good starting point. You'll find tons of other resources around MVC model binding out there.
I've really liked Steven Sanderson's Pro ASP.NET MVC 2 Framework if you prefer physical books.
UPDATE: looks like I've misunderstood what TempData is for and what it isn't. It definitively shouldn't be used to "keep certain session-wide data" as I asked initially (see ASP.NET MVC TempData Is Really RedirectData why). I've modified the question accordingly.
Has anyone used CookieTempDataProvider for TempData storage? Are there any caveats to watch out for (apart from keeping the session storage small)? Any issues with using it on Web farms?
I use the CookieTempDataProvider for our production web site and it seems to be working really well. We have a 2 server web farm. The site has been live for around 6 months, and we have experienced no issues, although the site does not get a lot of traffic.
I use the CookieTempDataProvider to store status messages that are to be displayed when a view loads. For example:
User edits a form and hits the save button. This is a post.
In the POST action method, I save the data, then push a confirmation message into TempData. Then I issue a RedirectToAction, to a GET action.
In the GET action method, I retrieve the message from the TempData and put it in the ViewData. Then I do my other data stuff and return the view.
On the view I check if the model has a message, and if so, display it.
Things to note:
I am using ASP.NET MVC 1.0.
I am using MVC Futures 1.0.
The CookieTempDataProvider did not work for me as is; I had to modify the code to get it working: see this post.
I'm trying to work out if there's a built in way in ASP.NET MVC to assign the form values that are POST'd back to the properties of the ViewModel that was originally sent to the View?
So I'm thinking along the ideas of decorating some of the properties in the ViewModel with an attribute and then reflecting over the ViewModel and using that name to extract values (and coerce) from the Form[] object.
However, I'd imagine that something like this was already built in and so don't want to re-invent the wheel here.
The problem that I'm trying to solve is that a user clicks a button on a form and the server validates the data and if there are errors we return the user to the form by using the same ViewModel to carry the data and thereby fill the values back into the form that the user originally entered.
(Yes, I'm also doing client side validation using JavaScript to make this lightweight but for security I have to repeat validation on the server.)
Ideas?
You can use UpdateModel or TryUpdateModel in your controller.
I recommend using one of the overloads in which you specify the fields to be updated.
This is discussed in detail on page 78 of the Wrox Professional ASP.net ebook (or echapter!)
I don't think MVC has anything like this built in, or at least I haven't seen anything. It would be nice though as many other MVC frameworks do this (struts for example).