MSDN Documentation

Understanding ASP.NET MVC Views

Views are a fundamental part of the Model-View-Controller (MVC) architectural pattern used in ASP.NET. They are responsible for presenting data to the user and are typically implemented using HTML, CSS, and JavaScript, often with server-side markup languages.

The Role of Views

• Presentation Logic: Views focus solely on how the data is displayed. They do not contain business logic or data access code.
• Data Binding: Views receive data (models) from the controller and render it into an appropriate format, usually HTML.
• User Interaction: Views can contain interactive elements like forms, buttons, and links that allow users to submit data or navigate.

View Engines

ASP.NET MVC supports various view engines that allow developers to choose the syntax and structure best suited for their project. The most common ones include:

• Razor: The default and most popular view engine. It uses a clean syntax with a @ symbol to embed server-side code within HTML.
• Web Forms (ASPX): An older view engine that uses <% ... %> syntax, similar to traditional ASP.NET Web Forms.

Razor View Syntax

Razor simplifies the process of embedding server-side code. Here's a basic example:

@model MyWebApp.Models.Product

@{
    ViewBag.Title = "Product Details";
}

<h2>@Model.Name</h2>

<p>
    Price: @Model.Price.ToString("C")
</p>

<p>
    Description: @Model.Description
</p>

<a href="@Url.Action("Index", "Products")">Back to Products</a>
        

In the Razor example above:

• @model MyWebApp.Models.Product declares the type of the model the view expects.
• @{} is used for code blocks.
• @Model.PropertyName accesses properties of the model.
• @ViewBag.Title accesses a dynamic property to set the page title.
• @Url.Action(...) is a helper method to generate URLs.

Layouts and Partials

To promote code reuse and maintain consistency, ASP.NET MVC views utilize layouts and partial views:

• Layout Pages: Define the overall structure of the application (e.g., header, footer, navigation). Views render their content within a specified section of the layout.
• Partial Views: Reusable chunks of HTML that can be rendered within other views. They are useful for breaking down complex views into smaller, manageable components.

View Helpers

ASP.NET MVC provides built-in HTML helper methods (like @Html.TextBoxFor, @Html.DropDownListFor) and URL helper methods (like @Url.Action) to simplify the generation of HTML elements and URLs. You can also create custom helpers.

Example: Rendering a List of Items

@model IEnumerable<MyWebApp.Models.Category>

<h2>Product Categories</h2>

<ul>
@foreach (var category in Model)
{
    <li><a href="@Url.Action("Details", "Categories", new { id = category.Id })">@category.Name</a></li>
}
</ul>
        

This example demonstrates iterating over a collection of models and generating links for each category.