partial view in mvc4 - asp.net-mvc-4

I am new to Jquery mobile and asp.net mvc4. In my application I have divided my page into three blocks(ui-block-a,ui-block-b,ui-block-c).These three blocks are in shared folder(_Layout.cshtml). Left side and right side blocks are partially viewed. In the middle block is normally viewed. When I perform any modification the partial view is also refershing.I want to load my partial view on my first time loading only. If I do any change on middle block the partial views should not be affected. please help how can
I do this?

Partial view doesn't mean it would be partially updated. It's just a small chunk of ui code wich is suitable to be grouped into a separated file for reuse.
you'll need to implement ajax functions into middle block when updating.
jQuery.ajax
would be the api you can refer to.

Related

jQuery Mobile does not process elements in Partial View

I'm converting my site from using jQueryUI to jQuery Mobile, and I'm having some trouble.
I have a page that lets users add new timesheet entries. They click the "Add" button and it retrieves a Partial View from the server right onto the page.
The problem is that jQuery Mobile is not applying to any of the elements in the Partial View.
How can I force jQuery Mobile to process my elements after they've been inserted into the page?
The short answer is that you can just trigger the create method on the parent element of where you inserting your partial view.
For example $('#container').trigger( "create" );
Alternatively most widgets can be manually initialized by calling them on the element, for example for a listview: $('#myListview').listview(). This can be useful if you have only a few elements that need to be enhaced and you don't want to traverse all the child elements of the container. You should also know that for many widgets there is also a refresh method which you can call if you add elements to it after it has already been initialized for example $('#myListview').listview('refresh).
Also have a look at the following Q & A from the JQM docs which deals with this issue and for an explanation as to why it is necessary to call these methods.
Question: Content injected into a page is not enhanced.
Answer:
jQuery Mobile has no way to know when you have injected content into a
page. To let jQuery Mobile know you have injected content that must be
enhanced, you need to either make sure the plugins are called to
enhance the new elements or trigger("create") on the parent container
so you don't have to call each plugin manually.

Where is the equivalent of WebForms' Master Page codebehind files in ASP.NET MVC?

Today is my first day working with MVC and I am trying to convert my existing Web Forms website into an MVC 4 site.
I have done some reading and am starting to understand how things work but one thing I can not figure out is for the new Layouts (replacing MasterPages) where is the equivalent to the codebehind file? In my current site I have a Master Page that defines the general look and feel but also runs some code in the codebehind to changes a few things dynamically (for localization and DB generated menu system).
So now that I am using MVC and Layouts I can not figure out where I would code all that at, can anyone please point me in the right direction?
(I know MVC does not have code behinds it uses controllers for it.)
As you Know MVC is three layer architecture.
Model
View
Controller
Model is the data entities. You need to store, or show the data.
Views are the html or presentation layer which would be rendered to users.
Controller are the code behind file all of your code would go in controller. It gets data from Models and apply business logic and then pass to views to show or get updated data from view and pass to models and then save to database.
_layout.cshtml file is present at path of ~/Views/Shared/_Layout.cshtml. It is master-page in mvc. You would see your partial-views contains
Layout = "~/Views/Shared/_Layout.cshtml";
this line at top of page. You can change master-page for any views and you can have multiple Layouts.
Layout contains many partial-views like left-navigation, Top-Navigation and content. each of which can be customized from controller.
Here are some links might help you:
MVC Tutorials
Introduction to MVC
Create a Base Controller class and make all your controllers inherit from it.
The MVC equivalent of WebForms' Master Page codebehind is then this Base Controller, where you can put code you need for multiple controllers.
How can I execute common code for every request?
You can't find any examples of what you're trying to do, because that's not how it's done in MVC. There is no equivalent to code behinds.
You're "trying to do" the wrong thing. MVC layouts are simply template files. They have no code behind, and they should have no functionality besides simple display logic.
MVC is a different paradigm from WebForms. You don't use have server-side controls like WebForms. Therefore the idea that you have content in the layout that does it's own thing violates the MVC principles.
You're basically stuck in what's known as the XY problem. That's where you are trying to achieve certain functionality X, and you believe to do that you need to do Y, so all you ask about is Y... when X is what you really need to be asking about.
Please explain the actual thing you are trying to do, and don't assume that it must be done in the way you've always done it. For instance, if you want to localize something, then ask how to localize something. If you want dynamic content somewhere, ask how to do that, but you need to be more specific about these individual problems, and not just gloss over them as you have done here.

What should I prefer to use widget or renderPartial in Yii's view?

I am confused when I should use a custom widget or renderPartial in my view files. Sometimes I use widget and sometimes I use renderPartial.
Widget
You use widget when your application logic is defined in a separate CLASS file and the logic is somehow separated and standalone.
Widget's are chosen when the functionality is repeatedly used elsewhere, on lot of pages.
renderPartial
You use renderPartial for VIEW files that you want to embed into something bigger, or when you want to print something without using the application layouts.
renderPartial is chosen when all the variables it need to access are already prepared in the current action.
Widget
You can use widget when your site has some common part like header and footer or sometime some kind filter which require on every page of site.
renderPartial
Take example of search form of yii crude which is called by using renderPartial because that serach form is changing according to requirement of pages.
Sorry for english.

ExtJS 4 MVC multiple instances of views and sub/child controller difficulties

I have encountered a problem with the MVC pattern in ExtJS 4. At least, I think I have. Having approached multiple people with this question, and having posted numerous times in the Sencha forums, I am now turning to a broader audience in hopes of getting either a light bulb or a confirmation.
Problem
Your application has the ability to open many different views, some of which themselves are mini-applications. Additionally, a user may wish to have multiple concurrent copies of a view open.
This application is a single-page client-side Javascript application.
The ExtJS 4 MVC model expects you to define all of your controllers in your Application class. These controllers are then initialized when the Application loads. Controllers keep track of views, models and stores.
When you initialize controller A multiple times, say to create more than one copy of a view, you end up with two views that reference the same data stores, and functionally send duplicate events to the Application event bus.
I have refactored my application by adding new prototype methods to Component and Controller to allow for both a) sub controllers (some of my controllers were getting pretty huge) and b) defining stores specifically for the view they work with. The models can still be defined on the controller, just for ease of use by handlers if you need to do something like grab a record from the server.
Question
My understanding of MVC would lead me to believe that models more directly relate to the View than then Controller. I asssssume that ExtJS 4 decides to attach stores (which I think can be seen as wrappers to a more classic model) to Controllers for purposes of encouraging re-use of loaded data, and to optimize away from having many copies of the same class instantiated. It seems to me, however, that one cannot do this if one intends to have many instances of a view available to the user. To my thinking, having many instances is an important option in an OO framework, hence why I have bucked the trend and implemented prototypes on some of the Ext base classes. (Thank you Ext.implement!).
Is there any way to have multiple concurrent instances of a view with different data loaded into them using the out of the box MVC classes and making uses of the provided setters, getters, etc?
I was faced with a similar problem:
Consider a tabpanel for a CRM type application which opens new instances of a view for each client. And say that tab view contains 3 or 4 row-editing gridpanels for interacting with different collections of data relating to that client.
The solution I came up with was based on this from the Sencha forums. In a nut shell, almost all events that are dispatched from a view contain a reference to the view itself. The handlers in my controller's control function all use these to get a reference to the correct view instance.
For dealing with the multiple instances of the same store needed for this, I took this to heart from that post:
For the Store instance on the view or a global one... depends on the
needs. If you are going to use globally then make it global. If you
only are going to need it on the view then put it on the view. MVC is
not a law, you can change it to fit your needs. Technically the
Controller part of MVC is suppose to be the middle man between the
View and Model parts but sometimes that's just not needed. I create
the Store in the view 95% of the time. I'll give you an example...
If you have a Store for products, you probably only need to reference
that Store in your Grid. That usually isn't needed for other parts of
the application. However, if you have a Store to load countries, I
often need it globally so I only have to load it once and can then
set/use that Store in several views.
So I just created the needed store's that relate to a view instance specifically, inside the view's initComponent method. The application did have a few global stores that I created as store classes following the MVC recommendations. It worked out nicely to encapsulate the view instance stores inside the view. Then I only needed one instance of the controller.
To answer your question specifically, currently, there is no ExtJS official recommendation or config for dealing with multiple instances of the same view that use the same store constructor. I have spent some time looking for something like that and the best I have found was this recommendation from one of their forum moderators.
I don't think you ever need more than 1 instance of a controller, regardless of how many views/models you have. See functional example here:
http://whatisextjs.com/extjs-4-extension/fieldset-w-dynamic-controls-7
This can be done, reasonably easily. You need to follow a few rules:
load your controllers at app startup. Don't unload them. Don't worry about the memory or time, it's pretty small even for hundreds of controllers, as long as you minimize and concatenate your js.
Never use the refs or views properties of a controller. You are going to use one instance of a controller, but multiple instances of views, so you never want a reference to a view.
only use event listeners in controllers. You are only going to listen to events on your views. You can always get a (temporary) reference to a view in the event handler via the "cmp" parameter in the handler.
To "launch" a view, create it and add it to another view. To destroy it, destroy it. You don't use a controller to launch a view. You can use the afterrender and beforedestroy events in the controller to add logic.
In ExtJS' MVC the controller is a Singleton for you view. I like how DeftJS thinks about MVC. Each instance of a view has an own instance of a controller. In this way you can put all "controlling rules" in a controller for a particular part of your view, and this will be instantiated only when the view opens.
I did not have any experience how I could use multiple Defts JS apps in the same project.
Of course. What led you to believe otherwise?
Here is an example of creating a custom View which extends from a Window component. You can run this method many times from the same controller and each time you will get a new instance of a View.
"this" refers to a controller that code runs in:
this.getRequestModel().load(requestID,{ //load from server (async)
success: function(record, operation) {
var view = Ext.widget('requestEdit',{
title: 'MyRequest '+requestID
});
var form = view.down('form');
form.loadRecord(record);
}
});
How do you create your views? I see no reason why you cannot pass a different store or config data to every object. Some code samples would help for what exactly you are doing. For example, we have a similar sounding application, and everything is done with extensions. So, if we need a grid, we run
Ext.define('MyApp.grids.something',{
extends:'Ext.grid.panel'
//...
These classes are predefined. Then, when a controller or view is loading this grid, they are using
var grid=Ext.create('MyApp.grids.something',{id:'unique',store:mystore});
As you can see, we can pass in different config options to the same grid each time it is created. We can treat this exactly as you would treat
Ext.create('Ext.grid.Panel');
Except of course that we make some options predefined, and some non-override-able, and so on.
Hope this helped.
Check out this post. The idea there is to take some configuration (like store and itemId) from view config and put it into the viewport config:
// .../app/view/Viewport.js
Ext.define('MyApp.view.Viewport', {
// ...
items: [
// ...
{ xtype: 'testview', store: 'Store1', itemId: 'instance1' },
{ xtype: 'testview', store: 'Store2', itemId: 'instance2' }
]
});
The problem with store will be solved, obviously. Different itemIds will enable you to handle events properly.

Need to access the Page object in Global.asax in the PreRequestHandlerExecute

I have a huge website (containing around 5000+) pages. There is a theme functionality in the website where user can choose different colors for their profile. Now i want to use the ASP.net theme feature and put different CSS (for different colors) in the theme folder and in Global.asax i want check the user theme and render appropriate link element with the css. But my problem is, i am not able to access the Page element for adding the link in the page.
Here is my code
Dim page As System.Web.UI.Page = TryCast(System.Web.HttpContext.Current.Handler,System.Web.UI.Page)
page.StyleSheetTheme = "Black"
But when i run this code I get a Null reference error.
P.s : My application is very huge so its not possible to have a master page or a base class and inherit it in every page.
Please suggest.
The page is not available in PreRequestExecute. This function is called before asp.net steps in to handle things, and asp.net is responsible for the page. Think of PreRequestExecute as being earlier in the scheme of things, like when IIS is first trying to figure out what to do with this thing it has, the thing is not even a page yet.
You might want to look into some of the other events that you can hook, there are events that would take place after the page has loaded that may allow you to do what you are suggesting.
Rather than going into global.asax for this, consider using master pages. One possibility is to have nested master pages, where the first master page sets up overall layout, and the nested master handles the theme. (Or one of several nested master pages, all referencing the same top-level master page). If necessary, you can use the PreInit event in the page to change master pages, and select the master that matches your theme selection.
You can centralize this function by having your own class that inherits System.Web.UI.Page, and have all your own pages inherit this new class. Handle the PreInit event there. (As well as other useful functions, like page-level handling of unhandled exceptions, general security issues, etc.
EDITED TO ADD: As #aepheus correctly notes, the page hasn't been instantiated at the PreRequestHandlerExecute event. So there's no page class you can access.