Introduction to ASP.Net 6

Level : Beginner

Mentor: Shailendra Chauhan

Duration : 00:05:00

Model in ASP.NET MVC

In ASP.NET MVC, a model represents the application's data and business logic. It defines the structure of data used by the application, ensuring a clear separation of concerns. Models are used to interact with databases, perform validation, and provide data to views.

Example

public class Product
{
  public int ProductId { get; set; }
  public string Name { get; set; }
  public decimal Price { get; set; }
}

Creating a View

Views in ASP.NET MVC are responsible for rendering the HTML markup that will be sent to the client's browser. They are typically associated with controller actions and use Razor syntax to generate dynamic content.

Example

@model MyWebApp.Models.Product
<h1>@Model.Name</h1>
<p>Price: $@Model.Price</p>

Passing Data to Views

Controllers specify views and pass data to them using model objects, ViewData, ViewBag, or strongly typed view models. This allows views to display dynamic content based on the data provided by the controller.

Example

public IActionResult ProductDetails(int id)
{
  var product = _productService.GetProductById(id);
  ViewData["Title"] = "Product Details";
  ViewBag.Category = "Electronics";
  return View(product);
}

Partial Views

Partial views are reusable components in ASP.NET MVC that allow you to break down complex views into smaller, manageable pieces. They can be used to render specific sections of a page or to encapsulate a self-contained UI element.

Example

<!-- _ProductPartial.cshtml -->
@model MyWebApp.Models.Product
<h2>@Model.Name</h2>
<p>Price: $@Model.Price</p>

Asynchronous HTML Helper

Asynchronous HTML helpers in ASP.NET MVC allow you to generate HTML elements asynchronously, enabling non-blocking rendering of web pages. This is particularly useful for handling long-running operations without blocking the UI.

Example

@await Html.ActionAsync("GetProductData", "ProductController")

Access Data from Partial Views

To access data in a partial view, you can use the @model directive or pass data via ViewData or a strongly-typed model from the parent view or controller. This allows partial views to display data in a context-aware manner.

Example

<!-- Accessing data passed from the parent view -->
<h2>@Model.ProductName</h2>
<p>Price: $@Model.ProductPrice</p>

Adding a Model Class

When developing an ASP.NET Core MVC application, you often create model classes to represent the data structure of your application. This involves defining the properties and attributes of your model entities.

Example

public class Customer
{
  public int CustomerId { get; set; }
  public string Name { get; set; }
  public string Email { get; set; }
}

How Controllers Specify Views

In ASP.NET Core MVC, controllers specify which views should be rendered based on user requests. Controllers use methods to return specific views or action results, defining how the application responds to different requests.

Example

public IActionResult Index()
{
  return View(); // Renders the "Index" view
}

View Discovery

ASP.NET Core MVC uses a convention-based approach to discover views. It looks for views in specific locations based on the controller's name and action method, making it easy to locate and render the appropriate views.

Strongly-Typed Data (ViewModel)

Strongly typed views in ASP.NET Core MVC use view models to pass data to views. These view models are classes designed to hold data specific to a view, ensuring type safety and data integrity.

Example

public class ProductViewModel
{
  public int ProductId { get; set; }
  public string Name { get; set; }
  public decimal Price { get; set; }
}

Using ViewData and ViewBag Simultaneously

ASP.NET Core MVC allows you to use both ViewData and ViewBag to pass data to views. ViewData is a dictionary-like object, while ViewBag is a dynamic property bag. You can use them simultaneously to provide data to your views.

Example

ViewData["Title"] = "Product Details";
ViewBag.Category = "Electronics";

Dynamic Views

Dynamic views in ASP.NET Core MVC allow you to create views without a specific model. These views can work with data of various types or even no specific type, providing flexibility in rendering content.

Example

@{
  var message = "Hello, World!";
}
<h1>@message</h1>

Lab in ASP.NET Core MVC

Labs in ASP.NET Core MVC are practical exercises or projects that help developers gain hands-on experience in building web applications. These labs often involve creating models, views, and controllers, and working with various features of the framework.

When to Use Partial Views

Partial views in ASP.NET Core MVC are used when you need to render a portion of a view independently or when you want to reuse a specific UI component across multiple views. They help in modularizing your application's interface.

Declare Partial Views

To declare a partial view, you create a Razor view file with a leading underscore (e.g., "_PartialView.cshtml"). These files can be used within other views and are typically stored in the "Views/Shared" folder.

Reference a Partial View

To reference a partial view from another view, you can use the @Html.Partial or @await Html.PartialAsync methods to include the partial view's content within the parent view.

Example

@await Html.PartialAsync("_ProductList")

Use a Partial View in a Razor Pages PageModel

In Razor Pages, you can use partial views within the PageModel to render reusable UI components, promoting code reusability and modularization of your Razor Pages application.

Example

public IActionResult OnGet()
{
  // ...
  return Partial("_ProductList", productList);
}

Use a Partial View in a Markup File

Markup files like .cshtml can include partial views using the <partial> tag, simplifying the inclusion of shared UI components in your views.

Example

<partial name="_ProductList" model="Model.Products" />

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