I have a page which consists of multiple partial views uploaded by a user. I have customized the Razor viewEngine to look at different locations for the .cshtml files.
Now if i'm rendering a partial view _abc.cshtml(found on my external location) and this partial view requires a viewmodel AbcViewModel, whats the best way to deal with this?
option 1: I have a DB entry that specifies _abc.cshtml uses AbcViewModel. So once I find the partial view, i'll know which viewmodel to use..In this case the ViewModel resides in the solution itself.
Using reflection I can get the class
Assembly assembly = Assembly.GetExecutingAssembly();
AbcViewModel viewModel= assembly.CreateInstance("AbcViewModel") as AbcViewModel;
I was wondering if there is a way that I could have the viewModel at an external location..this way I can extend my application..
Related
I am new to ASP.NET Core and have some trouble with binding global models and viewmodels to razor views. My application is a mixture of Web API and MVC with razor views.
My goal
When I open an ASP.NET MVC page, I need to instantiate a model by loading it from the database (DbContext service) based on an id received in a cookie. I want to use this model object globally in every view or partial view.
Current Implementation
I can access the cookies in action methods of page controllers, so that I have to load the model from the DbContext in every action method and bind it as viewmodel to target view. This is not practical, because I have to do this in every page controller, because I need that model object on all pages in my navigation pane.
Idea
I think it should be possible to access to Cookies and dbcontext within Startup.cs and bind the model object to _ViewStart.cshtml, so that it is accessible globally in every view or partial view. Even this approach were correct, I do not have any idea how the code would look like. Because I am learning Web-Apps with .NET Core by learning by doing and try and error at the moment. :(
UPDATE
I have a layout page _Layout.cshtml, which includes partial views like the _NavPane.cshtml. My goal is to pass a Model object to the _Layout, which is instantiated via loading from the database (I have a service IMandantRepository for this purpose) and dependent on a cookie.
That model object is needed on every page request. That's why it would be a better practice to load the model object outside the MVC page controllers and pass it to them (what I can not implement technically).
I tried to find a solution by myself and ended up in following interim ugly solution. Following is the content of the _ViewStart file. On the bottom I assign the needed global variables, which I can use in every view or partial view.
This solution has at least two disadvantages:
The model object is possibly loaded redundantly.
Too many program logic in a view file.
#inject MyProject.Data.IMandantRepository mandantRepo
#{
// Main layout template
Layout = "_Layout";
// Define default values
bool showAdminSection = false;
string src = "/images/logos/nologo.png";
// Read cookie value
string currentMandantUid;
Context.Request.Cookies.TryGetValue("currentMandant", out currentMandantUid);
// Load mandant from the database
var thisMandant = mandantRepo.GetMandantByUid(currentMandantUid);
if(thisMandant is Mandant){
src = "data:image/*;base64," + thisMandant.GetBase64Logo();
showAdminSection = thisMandant.Abbr == "AdminMandant";
}
// Assing global variables to ViewData
ViewData["CurrentMandant"] = thisMandant;
ViewData["logoSrc"] = src;
ViewData["showAdminSection"] = showAdminSection;
}
This is an example code in ConfigureService() of Startup.cs. You can register your dbContext class in this way.
services.AddDbContext<BookStoreContext>( options =>
options.UseSqlServer(_configuration.GetConnectionString("DefaultConnection")));
I am having trouble with a _Partial in the master _Layout.
My _MemberList (Partial) have its own ViewModel (MemberListViewModel)
and I want to load this Partial in the _Layout maybe through a BaseController with a Layout Attribute or something, which is the best solution for this ?
The _MemberList is dynamically loaded, it depends on what the user selects.
It worked before when I had a strongly typed ViewModel in the _Layout, but when I try to load other ViewModels it asks for the one in the _Layout, so I guess I have to find another solution for this.
So what I need is a "dynamically loaded list in the _Layout(master) using a _partial".
Sample would be great!
Thanx
I have a C#.Net web app and I am trying to access one of the HTML/ASP Text Boxes in the Controller for the Edit View of my Proposal model. In a non-MVC app, I was able to do this using Control.ControlCollection.Find(). Is there an equivalent for a MVC3 project?
You ask for an equivalent of Control.ControlCollection.Find() in MVC?
In MVC your controller is not aware of controls.
The controller just receives data via parameters and returns data via the function result.
What do you want to do with the control in your controller code?
If you want to access the value, you should bind it to a parameter:
View:
<input name="MyControl" type="text" />
Controller:
public ActionResult MyAction(string MyControl) {
// MyControl contains the value of the input with name MyControl
}
The MVC pattern was designed to keep things separated.
The View has no knowledge of the controller at all
The Controller only knows that a view exists and what kind of data that it needs. It do not know how the data is render.
Hence, you can never get information about controls/tags in the view from the controller. You need to use javascript/jQuery in the view and invoke the proper action in the controller.
In an MVC-application you don't have controls like in a webform-application.
In MVC you collect your required data in the controller and pass it to the view.
Typicaly the view is a HTML-page with embedded code.
In opposite to controls in webforms which produce HTML and handles the post-backs in MVC you have to do all this manually. So you don't have controls with properties and events wich you can access easily in the controller and you have to handle all your posts with your own code.
Thats sounds as it is a lot of more work - and indeed it could be if you implement the behaviour of complex controls - but MVC applications are much better to maintain and you have 100% influence to the produced HTML.
Well probably i am late for this but it should help others in future...u can store ur value in hidden field in view and then access that value in controller by following code..
Request.Form["hfAnswerOrder"].ToString();
Point - hfAnswerOrder is the ID of the hidden field
My Control in cshtml page..
#Html.Hidden("hfAnswerOrder", Model.Answers.ToList()[0].AnswerOrder)
I have a custom CMS built with ASP.NET WebForms (you can see it in action at Thought Results). Now I want to build it using ASP.NET MVC 3 (or even 4). I don't want to change the architecture that much, therefore, I need to dynamically load a Razor View, and dynamically run a Model Loader method, and give the model to the view dynamically, then render the view, and return the result rendered string, all done in server.
In ASP.NET WebForms, my code is:
string renderedString = "LatestArticles.ascx".LoadControl().GetReneredString();
Now, I'd like to be able to write a code line like:
string renderedString =
"LatestArticles.cshtml".LoadView().BindModel("ModelBinderMethodName").Render();
I know about many questions about rendering a view (view to string), but I didn't find what I want.
You may checkout RazorEngine.
Using ASP.NET MVC3 I created a new Razor view and gave it the same name as the existing .aspx view that I had been using. I noticed that controller continued to pick up the .aspx view (which has the same name as the action) which is pretty much what I expected. I then renamed the .aspx view and action picked up the razor .cshtml view.
So if I have two views called myview.aspx and myview.cshtml and an Action called MyView() that does a return View(), it will pick up the myview.aspx view and return that.
How does MVC3 decided which view-type to default to?
Is there a way to change this default behavior to prefer a razor view over an .aspx view?
Everything stems down to the order of view engines in the ViewEngines.Engines collection. Here's how the ViewEngines static constructor looks like (as seen with Reflector in ASP.NET MVC 3 RTM):
static ViewEngines()
{
ViewEngineCollection engines = new ViewEngineCollection();
engines.Add(new WebFormViewEngine());
engines.Add(new RazorViewEngine());
_engines = engines;
}
which explains why WebForms is the preferred view engine.
So you could perform the following grotesque hack in Application_Start to inverse the preference towards Razor :-)
var aspxVe = ViewEngines.Engines[0];
var razorVe = ViewEngines.Engines[1];
ViewEngines.Engines.Clear();
ViewEngines.Engines.Add(razorVe);
ViewEngines.Engines.Add(aspxVe);
I would imagine its down to the order in which view engines are registered. Earlier registered view engines will be queried first. If you want to change the order:
ViewEngines.Engines.Insert(0, ...);