MVC 6 introduction
§Slavomír Moroz
§2016

MVC Pattern
•Model-View-Controller architectural pattern for user-interface design (1970 – 1980)
•Ruby on Rails, ASP.NET MVC, Spring MVC, …
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§Model – state of an aspect of the application
§View – displays user interface using provided model
§Controller – handles user interaction by amending model and passing it to a view
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§https://docs.asp.net/en/latest/mvc/overview.html
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§MVC 6 introduction
File:MVC-Process.svg

Create MVC application from template
-Show structure, startup, bower, staticfiles

Routing
•Convention-based routing
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§routes.MapRoute(name: "Default", template: "{controller=Home}/{action=Index}/{id?}");
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•Attribute routing
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§[Route("api/[controller]")]
§public class ProductsController : Controller
§{
§  [HttpGet("{id}")]
§  public IActionResult GetProduct(int id)
§  {
§    ...
§  }
§}
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§https://docs.asp.net/en/latest/mvc/controllers/routing.html
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§MVC 6 introduction

Browse default UI showing controllers in action
Create an route without controller (for HomeController)
Mixed routing – RouteAttribute overrides conventional
IActionConstraint – HttpPost, ActionName…

Controllers
•In ASP.NET MVC, a Controller is used to define and group a set of actions. An action (or action
method) is a method on a controller that handles incoming requests.
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•New controller instance for each request
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•Actions should return an instance of IActionResult (or Task<IActionResult> for async methods) that
produces a response.
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•https://docs.asp.net/en/latest/mvc/controllers/actions.html#defining-actions
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§MVC 6 introduction

Structure, activator, Go to link, show ActionResult helper methods

Views
•ASP.NET Core MVC views are .cshtml files stored by default in a Views folder within the
application.
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•When an action returns a view, a process called view discovery takes place.
•Unless a specific view file is specified, the runtime looks for a controller-specific view first,
then looks for matching view name in the Shared folder.
1.Views/<ControllerName>/<ViewName>.cshtml
2.Views/Shared/<ViewName>.cshtml
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•When an action returns the View method, like so return View();, the action name is used as the
view name
•A view name can be explicitly passed to the method (return View("SomeView");).
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§https://docs.asp.net/en/latest/mvc/views/overview.html
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§MVC 6 introduction

Edit index, remove the markup, put some label in it. Show bootstrap doc for classes.

Razor
§MVC 6 introduction
https://docs.asp.net/en/latest/mvc/views/razor.html

Implicit expression @datime
Explicit <p>Last week this time: @(DateTime.Now - TimeSpan.FromDays(7))</p>

ViewData (ViewDataDictionary Class)
•Represents a container that is used to pass data between a controller and a view
•Controllers writes the data, view reads.
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•ViewData.Model – passed model
•ViewData.ModelMetadata – set o information about model
•ViewData.ModelState – validation messages
•ViewData[“something”] – additional data
•also accessible via ViewBag.
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§https://msdn.microsoft.com/en-us/library/system.web.mvc.viewdatadictionary(v=vs.118).aspx
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§MVC 6 introduction

ViewData.Model = X vs. return View(X)
ViewData[“”] vs Viewbag
Show example of both

Layouts
§MVC 6 introduction

Show title

Layouts
•Specifying a Layout
§@{
§    Layout = "_Layout";
§}
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•Layout must call RenderBody. Wherever the call to RenderBody is placed, the contents of the view
will be rendered.
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•Running Code Before Each View
§If you have code you need to run before every view, this should be placed in the _ViewStart.cshtml
file.
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§https://docs.asp.net/en/latest/mvc/views/layout.html
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§MVC 6 introduction

Sections
•RenderSection(…) in layout (usually)
•Used for view-specific HTML that is not part of body (RenderBody())
•Side bars, adds, action-specific content
•Scripts (~/Views/Shared/_Layout.cshtml)
•Not required to be defined in all views (usually, required: false)
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§MVC 6 introduction

Show scripts section
Add to home:
@section scripts {
<script>
    alert("Welcome! Welcome!");
</script>
}

View model
•Models folder
•Represent state of a particuallar aspect of the application
•Each controller should have a sub-folder for its models
•Models are usually named by corresponding Actions
•Always prefer strongly-typed model to a ViewBag or ViewData
•Models should be POCO objects without any business logic
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§https://en.wikipedia.org/wiki/Plain_Old_CLR_Object
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§MVC 6 introduction

Show scaffolding
Switch to project before from zip folder
Show Index action – view, model, controller, automapper mapping

View helpers
§@model MyProject.Models.Product
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§@using (Html.BeginForm())
§{
§    <div>
§        @Html.LabelFor(m => p.Name, "Name:")
§        @Html.TextBoxFor(m => p.Name)
§    </div>
§    <input type="submit" value="Create" />
§}
§MVC 6 introduction
§@model MyProject.Models.Product
§@addtaghelper "Microsoft.AspNet.Mvc.TagHelpers"
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§<form asp-controller="Products" asp-action="Create" method="post">
§    <div>
§        <label asp-for="Name">Name:</label>
§        <input asp-for="Name" />
§    </div>
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§    <input type="submit" value="Save" />
§</form>
https://docs.asp.net/en/latest/mvc/views/tag-helpers/index.html
https://msdn.microsoft.com/en-us/library/system.web.mvc.htmlhelper_methods(v=vs.118).aspx

Add link to layout to games index
Details vs create views
Model display attributes
Import file with inject and usings

Route constraints
•Route constraints generally inspect the route value associated via the route template and make a
simple yes/no decision about whether or not the value is acceptable.
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•Avoid using constraints for input validation, because doing so means that invalid input will
result in a 404 (Not Found) instead of a 400 with an appropriate error message.
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•template: “edit/{id:int}“
•defaults: new { controller=“IdObjectController", action=“Edit" }
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•template: “edit/{guid:guid}“
•defaults: new { controller=“GuidObjectController", action=“Edit" }
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•https://docs.asp.net/en/latest/fundamentals/routing.html#route-constraint-reference
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§MVC 6 introduction

Add id rule to routes, create game with integer codename

Model validation (server)
§MVC 6 introduction

Add attributes and IValidatableObject to view mode create
Show validation place holders in view
Show modelState check
Post – redirect – get

Model validation (client)
•Unobtrusive validation (linked with JQuery)
•Supports only attribute validators (doesn’t support IValidatableObject)
•Custom attributes that implements IClientModelValidator
•Hard to localize
§Setup
•Install nugget package Microsoft.JQuery.Unobtrusive.Validation
•Link scripts in your layout:
•JQuery
•JQuery-validate
•JQuery-validate-unobtrusive
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§MVC 6 introduction

Do nothing

Partial views
•Html.Partial(…) – displays view of given name (no controller/action is called)
•Html.RenderAction(…) – calls a controller‘s action, rendering its result
•always use PartialViewResult
•Usually view name starts with an underscore
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§https://docs.asp.net/en/latest/mvc/views/partial.html
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§MVC 6 introduction

Place _ValidationScriptsPartial to script section in create view
Explain void methods in views – in link there is a difference between Partial() and RenderPartial

Model binding - passing data
§MVC 6 introduction


Customize binding behavior
•MVC contains several attributes that you can use to direct its default model binding behavior to a
different source.
•[BindRequired]: This attribute adds a model state error if binding cannot occur.
•[BindNever]: Tells the model binder to never bind to this parameter.
•[FromHeader], [FromQuery], [FromRoute], [FromForm]: Use these to specify the exact binding source
you want to apply.
•[FromServices]: This attribute uses dependency injection to bind parameters from services.
•[FromBody]: Use the configured formatters to bind data from the request body. The formatter is
selected based on content type of the request.
•[ModelBinder]: Used to override the default model binder, binding source and name.
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§https://docs.asp.net/en/latest/mvc/models/model-binding.html
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§MVC 6 introduction

Add bind attribute, list all desired properties, security

Collections binding
§MVC 6 introduction

Primitive array not working in demo from lecture 5 2015 cos of checkbox false value which is adding
extra value to non indexed array.

AntiForgeryToken
•Protection against CSRF attacks.
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•Render token in form
•generates the anti-forgery token with the Form Tag Helper
•<form asp-action="Edit">
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•Validation in controller
•[ValidateAntiForgeryToken] attribute
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§https://en.wikipedia.org/wiki/Cross-site_request_forgery
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§MVC 6 introduction

Context
•HttpContext (IHttpContextAccessor service dependency injection)
•Request
•Response
•Session data
•Authentized user
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•ActionContext (IActionContextAccessor service dependency injection)
•Action metadata
•ModelState
•RouteData
•Encapsulates information about a route.
•Route parameters and values
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§MVC 6 introduction

Resources
§https://docs.asp.net/en/latest/mvc/overview.html
•Complete documentation
•MVC part is well written
•Still in progress, some parts are missing
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§https://docs.asp.net/en/latest/tutorials/first-mvc-app/controller-methods-views.html
•Quick start tutorial
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§MVC 6 introduction

Mention config override from environment variable, useful for source control