I am developing a single page application in ASP.NET MVC. The ASP.NET Framework version is 4.5 and the MVC version is 4. I am wondering if ViewComponents in ASP.NET Core might help me with my problem.
The Problem
The application has a single "proper" Index view and multiple child/nested partial views inside it that depend on some parent views' data, for example:
Index > GridPartial --> RowInfoPartial > AdditionalRowInfoPartial
where > denotes nesting, i.e. GridPartial is nested inside Index and AdditionalRowInfoPartial is nested inside RowInfoPartial; and --> denotes dependency injection, i.e. both RowInfoPartial and AdditionalIRowInfoPartial depend on some data from GridPartial.
Ideally, I would like to only show what I need to show, but unfortunately, it is not the case right now. All the nested partial views are rendered synchronously when the application is loaded, meaning loading the application is extremely slow. Moreover, because of dependencies, many partial views have to call their corresponding actions in the controller to pass their dependencies to business logic and show the correct data on the client, which slows the loading time even further.
The Solution (?)
I've read up on ViewComponents in ASP.NET Core, and they seem to satisfy all my needs:
They can be invoked asynchronously, to reduce loading time and only show views when needed
Supports controller dependency injection
Supports business logic
I want to make sure that ViewComponents do indeed help me solve my problem before I migrate to ASP.NET Core. Is my understanding of this technology correct, or is there some other way of solving my problem without having to migrate to ASP.NET Core?
Related
My team maintains a very large .Net Core 2.1 web site. Lots of controllers, lots of services that get injected into the controllers via constructor injection.
Sometimes due to developer error a service class is no longer added to the DI container during startup. Obviously this leads to an exception when MVC tries to construct a controller that relies on that service (in response to an incoming request).
Problem is that this may affect only some lightly used controller, so our (far from perfect) regression testing doesn't pick up the regression bug. But it is still bound to be picked up by one of our (very demanding) customers.
I though of writing a unit test that would
Instantiate a ServiceCollection class (that implements IServiceCollection);
Call our own method that adds all services to that service collection (the same method used during normal startup);
Find all controllers through reflection, and try to construct them the same way MVC does - by getting dependent services from the DI container.
So my question is:
Does this approach make sense?
Is there an example somewhere that I could use?
Failing an example, how would I achieve 1) and 3) ?
Now i have asp mvc 5 .net framework project and handlers (ashx files with custom logic) to process customer needs (i.e. pricelists in custom format).
I intend to move to asp core, and the question : is there an equivalent to handler?
Articles on internet suggest to put logic to middleware, but this is inconvenient way in my case.
Can you explain what do you need that middlewares cannot provide them for you?
Middlewares are built in a way that you can completely migrate from old Http Handlers/Modules to them.
https://learn.microsoft.com/en-us/aspnet/core/migration/http-modules?view=aspnetcore-2.1
Razor pages with it's own logic and model best way to substitute custom handlers in my case
You could use Middleware or Interceptor for tracking any incoming request.
The most important difference between them is that, you could use interceptor per any action too - for this you should use dependency injection.
I have to rebuild an existing asp.net application using asp.net mvc 4 and I'm facing a design issue as I'm not confident enough with my mvc skills yet.
The existing application is for subscribing to insurance premium. The input sceen has controls for filling info about:
client details
risk detail: the risk can be of different types (Car, Truck) and the controls are dynamic. We have inheritance here with a RiskBase class, then RiskCar and RiskTruck.
Now, I'm trying to figure out how this would map to the MVC architecture.
Let's say I have a Contract business object as follow:
Contract{
Client theClient
RiskCar theRisk
}
Should I create one ViewModel for the entire page (View) ? I'd be tempted to create a partial View for the Risk but then it would have to be a different View for each type of Risk. How can I manage that ? What would the ViewModel looks like for the parent View ?
I’m aware that not everyone uses a thorough architecture when developing an MVC application but let’s assume I have the following architecture:
App.Core --> Class Library (POCO or Domain objects)
App.Data --> Class Library (Repository and Entity Framework)
App.Service --> Class Library (Service layer with all business logic)
App.Web --> asp.net MVC 3.0 project
App.Data --> Has a reference to App.Core
App.Service --> Has a reference to App.Core and App.Data
App.Web --> Has a reference to App.Core and App.Service
Inside our MVC application we try to follows this approach:
Inside our Controller (within a method), we instantiate a ViewModel.
We fill that ViewModel calling methods from our App.Service Layer
Once the ViewModel is filled, we return it to the View (so the view
is now strongly typed).
This occurs 99.9% of the time. It is clean, we like it and it leverages itself pretty well..etc!
Now my question is the following:
If we decide to move our application to MVC 4.0 and start using the
new Web API approach, I’m not sure I fully understand where (or how)
it would fit in our current architecture?
Keep in mind, that we are open to change this around!
Should we create a new App.WebAPI layer that sits between the App.Service and App.Web?
This means inside our Controllers, we would no longer need to call the App.Service directly but instead the new App.WebAPI layer?
Or, leave the Web API inside the App.Web layer and make the Controllers call the other APIControllers which in turn would call the App.Service layer?
Not sure if I make any sense here…but please feel free to suggest anything as I’m curious on different inputs.
Thanks
There are a couple of cases to consider:
Do you want to make this Web API serve as service layer and data access for your MVC application? If, yes, then you should completely remove all references of App.Service from the ASP.NET MVC project and have it query the Web API instead to fetch the data. In this case the Web API sits between your ASP.NET MVC application and the data access. It is the Web API that talks to the service layer and exposes it over the HTTP protocol.
Or do you want to provide an additional API for your web site that can be used by other clients (other than web browsers)? In this case the ASP.NET MVC application and the Web API sit on the same layer. Both query your Service layer to fill view models, it's just that in the case of the MVC application you are passing those view models to views which in turn convert them to HTML whereas in the Web API layer you probably use slightly different view models but which are still populated from your service layer and are passed to the client used the corresponding serialization mechanism (JSON, XML, ...)
I know this is late but I was actually looking for the same advice and I found this post.
Wouldn't having "both the MVC and Web API sit within the same layer" mean more maintenance work on the code, or maybe duplication of code? isn't the mvc web considered as a browser client? .. to me it makes sense to have the WebAPI your only layer to everyone else and in turn it would call your service layer for processing.
What is the benefit of leaving both the Web API and the MVC talking directly to the service layer? Can't the web API be the wrapper around the service layer?
Clarified Updated Question - Start
In the official MVC 3 Getting Started-tutorial it seems to me that all we have to do to get ORM working are two steps.
First adding the simple MovieDBContext-code as described at the end of part 4 ..
public class MovieDBContext : DbContext
{
public DbSet<Movie> Movies { get; set; }
}
.. and second in the beginning of part 5, with a simple right-click on the Controllers folder we can auto-generate a MoviesController that implements CRUD()-functionality using Entity Framework by simply telling which Model to use.
Now when using the web-application we can already write and read from the database.
What would be the simplest (or a simple) way to get this done for our Movie-Model with NHibernate instead of using Entity Framework?
Clarified Updated Question - End
Original question (only for additional background-info):
I'm trying to create an ASP.Net MVC 3 application that uses NHibernate and Postgres.
Background Info
Development is done on Windows with Visual Web Developer Express, the production environment will be/should be Linux+Mono.
Steps that have worked so far:
An ASP.Net Dynamic Data Entities Web Application using Npgsql and Postgres as the DB.
Successfully run on Windows development machine.
(Following this tutorial)
An ASP.Net MVC 3 application without using a database/model yet:
Succesfully run on Windows development machine and deployed to Linux production environment using Mono and Nginx. (Only as a proof of concept for myself not as a web app used by the public.)
An ASP.Net MVC 3 application with a model using SQL Server Express as the DB.
Successfully run on my Windows development machine.
(Following the MVC 3 Getting Started-tutorial)
Question
So far I managed to get Postgres to work with a "Dynamic Data Entities Web Application" but with an MVC 3 Web app I'm stuck on where/how to start. For the last mentioned MVC-3-Movie-Webapp I want to switch the DB from SQL Server Express to Postgres using NHibernate and Npgsql (NHibernate since Mono doesn't support Entity Framework).
When you look at the end of part 4 there's the simple MovieDBContext-code
public class MovieDBContext : DbContext
{
public DbSet<Movie> Movies { get; set; }
}
and in the beginning of part 5, we autogenerate CRUD-stuff using Entity Framework by simply telling which Model to use.
(MoviesController.cs, Create.cshtml, Delete.cshtml, Details.cshtml, Edit.cshtml, and Index.cshtml)
So I have that working with Entity Framework and SQL Server Express, but how would I achieve the same result by using NHibernate? (doesn't have to be with postgres immediately, sticking with SQL-Server as a first step would be fine) (Hopefully with similar simplicity, but getting the result itself would be great)
I found a lot of old stuff and how I would manually map things, but what would be a good-up to date standard way of achieving this with NHibernate for MVC 3?
(The closest thing I found was the source code mentioned in this thread, but it's 64 MB unzipped I got several "Projects not loaded successfully"-errors and the author said he uses MVC 2 so I think it's a little over my head for being a complete NHibernate noob.)
I think showing how this is done could be very useful for others as well, since the original tutorial is very easy to follow and is linked as the official starting point for MVC 3 app-development on http://www.asp.net/mvc ("Your First ASP.NET MVC App").
So I think this would be a great up to date example about how to use NHibernate with MVC 3.
Actually, those automated things haven't helpful enough in real world applications. We have to separate concerns and by using DataContext in UI Layer is not a good practice because that dependency will cause problems like lack of test-ability, violation of best practices. I think you need to have following things of your project
Separation of Concern (Layered Architecture - UI Layer, Servie Layer, Domain Layer, Infrastructure Layer)
Generic Repository and Unit of Work wrapping (Database functionalities, ORM - EF, NHibernate, etc
In your Service Layer process repositories and unit of work processings and expose Data Transfer objects or your domain objects (POCOs) to UI Layer
Use IOC to inject dependencies will help you to minimize dependencies
Create Unit test and Integration tests
Use Continuous Integration and Source control prefer (Distributed: Mercurial)
Useful References:
(Sharp Architecture) http://sharparchitecture.codeplex.com/
(IOC Container) http://www.castleproject.org/container/
(Generic repository) http://code.google.com/p/genericrepository/
NuGet is your friend. Here's a good example of using NuGet to automatically wire in your dependencies and configuration pretty much automatically.
Hope this helps.
Suggestion, don't get hung up on all the automatic stuff that the tutorials are showing you. Microsoft is just trying to show that you can easily get things started if you don't try to do anything unique.
Now for your situation. When you're making a controller, you're wanting to bind that controller with a type of model that you created somewhere. With nHibernate I'm thinking that you'll have manually created these POCO's and that you're using one of the many ways to map those POCO's through nHibernate to your database.
You won't be able to use the Entity Framework options because they're depending upon the features of the framework to provide information on the object, database, etc. Easiest things is to just make a controller that either gives you the options for CRUD or use an empty controller to build up your own ActionResults.
Hope this helps some and good luck with your project.