MVC3 global predicate filter - asp.net-mvc-3

I am building an admin console and all controllers depend on a dropdown selection for customer.
I would like to move this customer selection to the layout and persist it across all controllers so that you do not need to select it everywhere.
What is the best way to go about doing this?
Thanks in advance.

Move the dropdown to your _layout.cshtml.
Create a BaseView that all views will inherit from and give it a property to store the Customers & Current Customer.
Create a BaseController method that will fill in a BaseView instance.
Store the currently selected customer on your session.
Create a Global Filter and have it check all views to see if they inherit BaseView. If they do it can convert them to a BaseView and then fill in the properties.
Write some code in the _layout that can use the View to fill in the dropdown. I'm a bit fuzzy here since my coworker actually did this part when we did something similar.
When the user changes the dropdown value you can use JSON to call an action method that will update the current customer in session.

I would consider writing HTML helper. You assume that all the birds can fly, but say one day you have another exceptional scenario and you no longer need this dropdown box. Alternatively include it in a partial view and render that view where you need it - it's only one extra line of code.
E.g.
#section main_content{
#{ Html.RenderPartial("MyPartialViewContainingDropDownBox"); }
}

Related

Mvc base viewmodel render data within layout

I have created a base viewmodel that all of my view models inherit from. That part is easy.
All views are bound to a viewmodel (all are inherited from the base view model)
Within the OnActionExecuted method I insert a true/false value onto a property within the baseviewmodel depending on some conditions.
From the view side of things. I have a single layout page that some how I want to be able to read the property's value and render a different partial view based on the value.
Is this possible? I dont want to have to add the code to each of the views but I don't think I should be binding the layout to my baseviewmodel either.
If I can stay away from inserting the value into the valuebag that would be great as I need to be able to access these values anywhere in the application via strongly typed names.
what you want probably isnt possible because as you call a view from the controller then first the code inside that view is executed and then the layouts code is executed
to achieve what you are doing you can do 2 things
1. make the logic inside the controller itself and then render the correct view
2.call the layout from the controller giving it the name of the partial view in some property of the model or in the viewbag
Not sure I quite follow the use case, but rather than trying to render out a partial view, have you thought about nesting your layout pages.
I think you should be able to override the layout in the onactionexecuted, so you can set the layout dependant on the bool and that layout will render only the correct option.
Look here for an example:
Nested layout pages with Razor
HTH
Si

How can i make reusable partialview in asp.net MVC 3

I want to make a partialview with 2 dropdownlists. DDL data have to generate from db. I am new in MVC. What will be the proper way to make this Partialview?
Thanks
(Assuming you're using Visual Studio)
Under Views folder in your project find a folder named "Shared" (or create it if doesn't exist). Right-click this folder, select "Add->View". In the dialog "Add View" specify view name, model type (if you wish) and set the checkbox "Create as a partial view". Model type should probably be a new model class with two List<string> elements.
Anywhere you need to use this view, include the markup
#Html.RenderPartial("YourPartialViewName", YourModel);
where YourModel has the same type as a model specified in partial view declaration.
From my experience it's better to create action and call RenderAction() passing relevant parameters than using RenderPartial(). The reason is that you need to pass a fully populated model to RenderPartial and that means you have to duplicate the code for populating this model in all the controllers that use this 'partial view'.
I found it much cleaner to create a separate action that can receive a number of parameters (ie. id of the object) and than perform all the required steps to populate the model (ie. load the object from database). You can mark that new action with ChildActionOnly attribute so it cannot be called directly.

Finding, loading and adding partial views dynamically

I've been tasked with converting an existing webforms application to mvc 3 razor.
The application currently has an aspx page which has a static header user control and "n" amount of other user controls which are dynamically created. In the code behind for the file, it is executing the below code in various specific sections to dynamically process user controls with information provided from the database.
I know how to statically create partial views, but being somewhat new to MVC, how would I go about defining this new "aspx" page and also to dynamically find, load and add the partial views (each equivalent to the below webforms code)?
btw, the code will be in C# as well.
Dim parent As Control = Page.FindControl(_moduleSettings.PaneName)
Dim portalModule As PortalModuleControl = CType(Page.LoadControl(_moduleSettings.DesktopSrc), PortalModuleControl)
parent.Controls.Add(portalModule)
I think I can do something like this when the page is rendering. I want to make it as simple as possible.
The "PaneName" will be set in the parent variable which determines where in the page it will be shown (Left, Right, or Main)
The "DeskTopSrc" is the name of the partial view to display.
So, take the code out of the code behind and place it in the main View. Perform the above processing logic in the View (boy, switching from aspx code behind to a View throws me a loop. I gotta get use to doing the processing in the View. Reminds me of Classic ASP, but the Razor syntax will help).
Display the partial view via the #Html.PartialView('partial view name'). This view might have a grid in it associated with a specific model.
Below is the part I am unsure about.
I've done database processing for a main View associated with a Controller, but not with a partial view that needs to do some database processing.
Perform any database processing logic (if any) for this partial view in the Controller associated with the main View (which contains this partial View).
In the Action Index method while looping over these "partial views", I can get the data and display the views....
Ahhh, I think I got it.....
After carefully thinking it through, if someone could help me out with the last statement here, I would greatly appreciate it.
1.Have partial views already statically created with the specific HTML markup that I need in the Views/Shared folder.
2.In the main View, I will already have
#Html.Partial(ViewData["partial_view_left"])
#Html.Partial(ViewData["partial_view_right"])
#Html.Partial(ViewData ["partial_view_main"])
statements in specific locations of the HTML which will render the partial views as I retrieve their names from the database.
3.In the Controller's Index method, I need to do the following:
a) Loop through the converted logic (from the CodeBehind of the existing WebForms page in the PageLoad event) in the Index action method of the new Controller which will load the partial views dynamically.
1) Find out where the partial view will be displayed (left, right, main) from the database via the "parent" variable.
2) Find out the name of the partial view that will be displayed from the database via the “DesktopSrc” variable.
eg: ViewData["partial_view_left"] = "left_view"; OR
ViewData["partial_view_right"] = "right_view"; OR
ViewData["partial_view_main"] = "main_view";
3) Right here is where I am unsure of how to properly display the partial view.
I need to have the equivalent of a webforms "Controls.Add" method to render each partial view from the Controller that I retrieve from
the database from step 3.a.2
What statement can I use in this Index method of the Controller that will accomplish this?
In other words, if I dynamically need to display several partial views inside of a parent view, how is this accomplished in MVC?
I know for each partial view, I can send over the model associated with it, but I just don't know how I can place several partial views inside the main view page at run time from one Action method.
If your partial views need to do some processing, like database retrieval, then you should use
#{Html.RenderAction("ActionName");}
This will call an action method (which doesn't have to be on the same controller) that can dynamically choose a view based on logic, and populate the ViewModel with data from the database.
public ActionResult ActionName()
{
var modelData = GetData();
return View(settings.DesktopSrc, modelData);
}

Viewmodel collection and other objects

Being a relative newcomer to MVC I'm musing over a little problem. I'm developing a page which relies on a collection of my viewmodel objects. All good. But, as the page has relatively complex functionality I need to get at other objects or collections of the main domain model to display in the UI. Admitedly rather more light weight objects. What's the best way to achieve this?
What I do is create a custom class to encapsulate ANY data I need to display in any certain view / action. So for my Admin areas User controller, I have a AdminUserIndexViewModel class that holds my list of user business objects. I also put any other data I need to display into this class.
For my AdminUserEditViewModel (that corresponds to my Admin Area, User Controller, Edit Action) I might have a single User class, which itself has its Roles attached to modify if need be. If you need to put other information like user settings, or preferences, etc...
If they are not part of the viewmodel you are currently working with then you can use Html.Action to call into another controller method to render another inline view through a controllers method.

MVC Get Control View HTML value

I was curious to see if its possible that from a controller (or else where) could I get a instance of a Control View pass it the model it requires and get back the html that it would output?
For example I have a Control View that builds a league table. This is fine for when using it on the site but I also want to put this league table into a html email that I send out... can I use the control view to do this or do I have to recreate the league table?
If you put the table itself in a partial view, you could easily use Html.RenderPartial() to get the output from it. If you go so far as having an action method that gets the appropriate data from your data store and returns the partial, you could even use Html.Action() (given that you use MVC2 or higher).

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