Tag Helpers in ASP.NET Core MVC

Tag Helpers in ASP.NET Core MVC

In this article, I will discuss Tag Helpers in ASP.NET Core MVC Applications with Examples. Tag helpers are one of the new features introduced in ASP.NET Core MVC. Please read our previous article discussing How to Create Custom HTML Helpers in ASP.NET Core MVC Applications. As part of this article, we will discuss the following pointers.

  1. What are Tag Helpers in ASP.NET Core MVC?
  2. Key Characteristics of Tag Helpers in ASP.NET Core MVC
  3. Types of Tag Helpers in ASP.NET Core MVC
  4. Built-in Tag Helpers Type in ASP.NET Core MVC
  5. How to Use Tag Helpers in ASP.NET Core MVC?
  6. Example to Understand Built-in Tag Helpers in ASP.NET Core MVC
  7. Generating Links using Tag Helpers in ASP.NET Core MVC Application
  8. Understanding Anchor Tag Helper in ASP.NET Core MVC
  9. Why should we use Tag Helpers over manually generating these links in ASP.NET Core?
  10. HTML Helpers vs. Tag Helpers in ASP.NET Core MVC
  11. Advantages and Disadvantages of Tag Helpers in ASP.NET Core MVC
  12. Real-Time Use Cases of Tag Helpers in ASP.NET Core MVC
  13. When to use Tag Helpers in ASP.NET Core MVC?
What are Tag Helpers in ASP.NET Core MVC?

Tag Helpers are a feature in ASP.NET Core MVC that simplifies the process of generating HTML elements in views. Tag Helpers allows developers to create HTML elements in Razor views with a more natural and semantic syntax.

They provide a way to generate HTML markup using server-side C# code while still maintaining the benefits of clean, readable, and maintainable markup.

In ASP.NET Core MVC views, you can use HTML Helpers or manually write HTML mixed with Razor code to generate dynamic content. While these approaches are functional, they can sometimes lead to less readable and maintainable code, especially when dealing with complex UI elements or adding server-side logic directly into the markup.

Tag Helpers addresses these challenges by allowing you to create custom HTML-like elements that are processed by the ASP.NET Core runtime. These elements are linked to server-side code and can generate dynamic content, handle URL generation, apply conditional attributes, and more. Tag Helpers promote cleaner and more maintainable views by separating UI logic from markup and enabling a more declarative approach to generating HTML.

Key Characteristics of Tag Helpers in ASP.NET Core MVC:

Here are some key characteristics and benefits of using Tag Helpers in ASP.NET Core MVC Applications.

  • HTML-like Syntax: Tag Helpers use an HTML-like syntax that is familiar to web developers, making it easier to understand and work with.
  • Separation of Concerns: Tag Helpers help separate UI logic from markup, promoting a cleaner and more organized codebase.
  • Reusability: Custom Tag Helpers can encapsulate complex UI components and behaviors, making them reusable across multiple views.
  • Intuitive Integration: Tag Helpers naturally integrate server-side logic into your markup, making the code more readable and coherent.
  • Encapsulation of Complexity: Complex server-side logic and conditional rendering can be encapsulated within Tag Helpers, making your views cleaner and more maintainable.
  • IDE Support: Tag Helpers provide better IntelliSense and tooling support in modern development environments.
Types of Tag Helpers in ASP.NET Core MVC:

ASP.NET Core MVC has two main types of Tag Helpers: Built-in Tag Helpers and Custom Tag Helpers. Both types of Tag Helpers contribute to simplifying the process of generating HTML elements in views, but they serve different purposes.

Built-in Tag Helpers:

These Tag Helpers are provided by default as part of the ASP.NET Core framework. They cover common scenarios and tasks, making generating HTML with dynamic behavior easier, such as generating links, creating forms, loading assets, showing validation messages, etc. Some examples of built-in Tag Helpers include:

  • <a asp-controller=”Home” asp-action=”Index”>Link</a>: Generates a link with a URL that’s generated by routing based on the specified controller and action.
  • <img src=”~/images/pic.jpg” asp-append-version=”true” />: Generates a <img> tag with a cache-busting query string to ensure the latest version of the image is fetched.
  • <form asp-controller=”Account” asp-action=”Login” method=”post”>…</form>: Generates a form element with the appropriate action attribute for the specified controller and action.
  • <input asp-for=”Username” />: Generates an input field with attributes based on the model property specified by asp-for.
Custom Tag Helpers:

We create These Tag Helpers to address specific needs in our application. Custom Tag Helpers allow us to encapsulate complex UI logic and generate HTML output based on our application’s requirements. Custom Tag Helpers are defined by extending the TagHelper class and overriding its methods. We can create custom attributes that correspond to properties on our Tag Helper class. Some examples of scenarios where custom Tag Helpers can be useful include:

  • Generating custom UI components with specific behavior and styling.
  • Wrapping third-party JavaScript libraries or widgets with HTML markup.
  • Simplifying the display of complex data structures.

To create a custom Tag Helper, you would define a class that derives from the TagHelper base class and override the Process method to generate the desired HTML output. You can then use your custom Tag Helper in your Razor views by referencing it with the appropriate HTML-like syntax.

Note: In this article, I will give an overview of Built-in Tag Helpers, and in our upcoming articles, I will discuss How to Create Custom Tag Helpers. Please read the following articles before proceeding to this article, as we will use Layout, ViewImport, and Bootstrap in this demo.

Built-in Tag Helpers Type in ASP.NET Core MVC:

In ASP.NET Core MVC, several built-in HTML Tag Helpers cover common HTML elements and scenarios. These tag helpers simplify generating HTML markup while still allowing you to incorporate server-side logic. Here are some of the types of HTML Tag Helpers available:

Anchor Tag Helpers (<a>):

These tag helpers generate hyperlinks. You can use them to create links to different actions, controllers, or URLs. Examples include:

<a asp-controller="Home" asp-action="Index">Home</a>
<a asp-controller="Home" asp-action="Details" asp-route-id="42">Details</a>
Form Tag Helpers (<form>):

These tag helpers generate HTML forms. They help create forms that post data to actions in your controllers. Examples include:

<form asp-controller="Account" asp-action="Login" method="post">
<!-- form fields -->
</form>
Image Tag Helper (<img>):

This tag helper generates image elements with the appropriate src attribute. You can use it to include images in your views. Example:

<img src="~/images/pic.jpg" alt="Picture">
Input Tag Helpers (Various Input Elements):

These tag helpers generate various types of input elements such as text boxes, checkboxes, radio buttons, etc. Examples include:

<input asp-for="Name" />
<input asp-for="IsAdmin" type="checkbox" />
Link Tag Helper (<link>):

This tag helper generates links to CSS stylesheets, helping you include styles in your views. Example:

<link rel="stylesheet" href="~/css/styles.css" />
Script Tag Helper (<script>):

This tag helper generates script elements, allowing you to include JavaScript code or link to external scripts. Example:

<script src="~/js/script.js"></script>
Authentication and Policy Tag Helpers:

These assist in rendering content based on the user’s authentication status or specific authorization policies. Example:

<authorize>Only authenticated users can see this content.</authorize>
<authorize policy="Admin">Only admin users can see this content.</authorize>
Cache Tag Helpers (<cache>):

These help cache portions of your views to improve performance by reducing the need to recompute content on every request. Example:

<cache>
<!-- Content to be cached -->
</cache>
Localization Tag Helpers:

These help render content based on the current culture and provide localized strings. Example:

<localized asp-culture="en-US">Hello!</localized>
Environment Tag Helper:

This tag helper conditionally renders content based on the hosting environment. It can be useful for including different content for development and production environments.

Partial Tag Helper:

This tag helper renders a partial view within another view. It’s useful for breaking down complex views into smaller components.

View Component Tag Helper:

This tag helper renders a view component within a view. View components are similar to partial views but offer more encapsulation and flexibility.

These are just a few examples of the built-in HTML Tag Helpers available in ASP.NET Core MVC. Each tag helper has its own set of attributes and properties that we can use to customize its behavior. Additionally, we can create our own custom tag helpers to address specific requirements in our application. Custom tag helpers allow us to encapsulate complex behaviors or generate HTML based on our application’s logic.

How to Use Tag Helpers in ASP.NET Core MVC?

Using Tag Helpers in ASP.NET Core MVC is relatively straightforward. Tag Helpers are designed to simplify the process of generating HTML elements with dynamic behavior and server-side logic. Here’s a step-by-step guide on how to use Tag Helpers in your ASP.NET Core MVC application:

  1. Create a New ASP.NET Core MVC Project: If you haven’t already, create a new ASP.NET Core MVC project using your preferred development tools.
  2. Add Views and Controllers: Set up your controllers and views as needed for your application.
  3. Understand Built-in Tag Helpers: Familiarize yourself with the built-in Tag Helpers provided by ASP.NET Core. These include helpers for generating links, forms, images, and more.
  4. Using Built-in Tag Helpers: Include the appropriate HTML-like syntax in your Razor views to use a built-in Tag Helper.

Using Tag Helpers in ASP.NET Core MVC can significantly enhance your views’ readability, maintainability, and reusability by separating UI logic from markup and providing a more intuitive syntax for incorporating server-side functionality.

Example to Understand Built-in Tag Helpers in ASP.NET Core MVC:

Let us understand How to Use Built-in Tag Helpers with an example in an ASP.NET Core MVC Application. So, create a new ASP.NET Core Application named TagHelpersDemo using the Model-View-Controller Project template.

To make the Built-in Tag Helpers available for all the views of our application, we need to import the tag helpers inside the _ViewImports.cshtml file. We need to import them using the @addTagHelper directive, as shown below.

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

The @addTagHelper makes the built-in tag helpers available in the application, defined in an assembly called Microsoft.AspNetCore.Mvc.TagHelpers. Here, the wildcard “*” specifies that all the Tag Helpers are made available.

Generating Links using Tag Helpers in ASP.NET Core MVC Application:

Let us understand this with an example. First, create a class file named Student.cs within the Models folder. Once you create the Student.cs class file, then copy and paste the following code into it. As you can see, this is a very simple Student Model having only five properties holding the Student Id, Name, Branch, Section, and Gender.

namespace TagHelpersDemo.Models
{
    public class Student
    {
        public int StudentId { get; set; }
        public string? Name { get; set; }
        public string? Branch { get; set; }
        public string? Section { get; set; }
        public string? Gender { get; set; }
    }
}
Modifying Home Controller:

Modify the Home Controller as shown below. Here, we have created two action methods. To simplify things and keep the focus on Tag helpers, here we have hard-coded the required student data within the action method. The Index action method returns a list of students to the view, whereas the Details action method takes the student ID as a parameter and returns that student information to the view.

using TagHelpersDemo.Models;
using Microsoft.AspNetCore.Mvc;

namespace TagHelpersDemo.Controllers
{
    public class HomeController : Controller
    {
        private List<Student> listStudents;
        public HomeController()
        {
            //Create a List of Students
            //In Real-Time, you will get the data from the database
            listStudents = new List<Student>()
            {
               new Student() { StudentId = 101, Name = "James", Branch = "CSE", Section = "A", Gender = "Male" },
               new Student() { StudentId = 102, Name = "Smith", Branch = "ETC", Section = "B", Gender = "Male" },
               new Student() { StudentId = 103, Name = "David", Branch = "CSE", Section = "A", Gender = "Male" },
               new Student() { StudentId = 104, Name = "Sara", Branch = "CSE", Section = "A", Gender = "Female" },
               new Student() { StudentId = 105, Name = "Pam", Branch = "ETC", Section = "B", Gender = "Female" }
            };
        }
        public ViewResult Index()
        {
            //Pass the Student List to the View to make the view as a Strongly Typed View
            return View(listStudents);
        }

        public ViewResult Details(int Id)
        {
            //Fetch the Student Details
            var studentDetails = listStudents.FirstOrDefault(std => std.StudentId == Id);

            //Pass the Student model to the View to make the view as a Strongly Typed View
            return View(studentDetails);
        }
    }
}

Creating Details View:

Create a view with the name Details.cshtml within the View=>Home folder, then copy and paste the following code.

@model TagHelpersDemo.Models.Student
@{
    ViewBag.Title = "Student Details";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<div class="row m-3">
    <div class="col-sm-8">
        <div class="card">
            <div class="card-header text-center">
                <h1>@Model?.Name</h1>
            </div>

            <div class="card-body text-center">
                <h4>Studnet ID : @Model?.StudentId</h4>
                <h4>Branch : @Model?.Branch</h4>
                <h4>Section : @Model?.Section</h4>
                <h4>Gender : @Model?.Gender</h4>
            </div>
            <div class="card-footer text-center">
                <a href="#" class="btn btn-primary">Back</a>
            </div>
        </div>
    </div>
</div>
Modifying Index View:

Now, in the index view, we have to provide the View button as a link, and when we click the View button, we need to display the Student Details. For example, we need to generate the following hyperlink. The number 101 is the ID of the student whose details we want to view.

/home/details/101

We have many different methods to generate a link in the ASP.NET Core MVC Application. Let us discuss all the possible options to generate a link, and then we will discuss why we should use Tag Helper over others in the ASP.NET Core MVC Web Application.

Method 1: Using HTML Element:

In this case, we need to use the anchor tag, and in the href attribute, we need to specify the path of the details action method along with the student id like <a href=”/home/details/@student.StudentId”>View</a>. So, modify the Index action method of the Home Controller as follows.

@model List<TagHelpersDemo.Models.Student>
@{
    ViewBag.Title = "Student List";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<div class="table-responsive">
    <table class="table">
        <thead>
            <tr>
                <th>ID</th>
                <th>Name</th>
                <th>View</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var student in Model)
            {
                <tr>
                    <td>@student.StudentId</td>
                    <td>@student.Name</td>
                    <td><a href="/home/details/@student.StudentId" class="btn btn-primary">View</a></td>
                </tr>
            }
        </tbody>
    </table>
</div>

With the above changes in place, run the application and navigate to the Root URL or Home/Index URL, and you should see the following page on the web browser.

Tag Helpers in ASP.NET Core MVC Applications with Examples

Once you click on the View button, it will execute the Details action method of the Home Controller by passing the Student ID value 101, and hence, you will see the following Details view of the Home Controller showing the Student details.

Tag Helpers in ASP.NET Core MVC Applications with Examples

Method 2: Using HTML Helpers

Using HTML Helper methods, we can also generate the link. So, we need to use the ActionLink Helper method to generate the link like @Html.ActionLink(“View”, “Details”, “Home”, new {id = student.StudentId}).

Here, the parameter View is nothing but the link text; the second parameter Details is the Action method name; the third parameter Home is the controller’s name, and the fourth parameter is object routeValues, which specifies the id parameter value. So, modify the Index.cshtml view of the Home Controller as follows to use the HTML Helper Method to generate the link.

@model List<TagHelpersDemo.Models.Student>
@{
    ViewBag.Title = "Student List";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<div class="table-responsive">
    <table class="table">
        <thead>
            <tr>
                <th>ID</th>
                <th>Name</th>
                <th>View</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var student in Model)
            {
                <tr>
                    <td>@student.StudentId</td>
                    <td>@student.Name</td>
                    <td>@Html.ActionLink("View","Details","Home", new {id = student.StudentId})</td>
                </tr>
            }
        </tbody>
    </table>
</div>

With the above changes in place, run the application and see if everything is working as expected.

Method 3: Using Tag Helpers:

To use Tag Helpers, first, we need to import the @addTagHelper directive in the _ViewImport.cshtml file. Along with the @addTagHelper directive, we also add the model namespace using the @using directive. So, modify the _ViewImport.cshtml file as shown below, which you can find within the Views folder.

@using TagHelpersDemo
@using TagHelpersDemo.Models
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

With these changes in place, you can now access the types defined with the above-using namespace throughout the application without re-specifying the namespace and all the tag helpers you can access from all the views. Next, modify the Index view of the Home Controller as shown below. Here, we are using Tag Helpers.

@model List<TagHelpersDemo.Models.Student>
@{
    ViewBag.Title = "Student List";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<div class="table-responsive">
    <table class="table">
        <thead>
            <tr>
                <th>ID</th>
                <th>Name</th>
                <th>View</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var student in Model)
            {
                <tr>
                    <td>@student.StudentId</td>
                    <td>@student.Name</td>
                    <td>
                        <a asp-controller="Home"
                           asp-action="Details"
                           asp-route-id="@student.StudentId">View</a>
                    </td>
                </tr>
            }
        </tbody>
    </table>
</div>

Now, run the application, and it should work as expected.

Understanding Anchor Tag Helper in ASP.NET Core MVC:

The Anchor Tag Helper in ASP.NET Core creates the standard HTML anchor (<a … ></a>) tag by adding new attributes such as:

  • asp-controller: It is used to specify the controller to target based on the routing system. If you omitted this, then the controller of the current view is used by default.
  • asp-action: It is used to specify the Action method to target based on the routing system. If you omit this attribute, the action rendering the current view is the default.
  • asp-route-{value}: It specifies the additional segment value for the URL. For example, asp-route-id provides value for the ‘id’ segment.

The value of the rendered anchor element’s “href” attribute is determined by the values of these “asp-“ attributes. As the name says, asp-controller specifies the controller’s name, whereas asp-action specifies the name of the action name. Similarly, the asp-route-{value} attribute includes route data in the generated href attribute value. {value} can be replaced with route parameters such as id, name, etc. Let us have a look at the following image for a better understanding.

Tag Helpers in ASP.NET Core MVC Applications

As you can see in the above image, manually generating the links is much easier than using HTML Helpers or Tag Helpers. Then why should we use HTML helpers or Tag Helpers over manually generating these links in ASP.NET Core?

Why should we use Tag Helpers over manually generating these links in ASP.NET Core?

In ASP.NET Core MVC, the Tag Helpers generate links based on the application routing templates. That means in the future, if we change routing templates, then the link generated by tag helpers will automatically reflect those changes made to the routing templates. So, the generated links work as expected without any trouble.

On the other hand, if we have hard-coded the URL paths manually, we need to change the code wherever we have hard-coded the path in our application when the application routing templates change.

Let’s understand this with an example. The following is the Main method of the Program class of our application.

namespace TagHelpersDemo
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var builder = WebApplication.CreateBuilder(args);

            // Add services to the container.
            builder.Services.AddControllersWithViews();

            var app = builder.Build();

            // Configure the HTTP request pipeline.
            if (!app.Environment.IsDevelopment())
            {
                app.UseExceptionHandler("/Home/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.MapControllerRoute(
                name: "default",
                pattern: "{controller=Home}/{action=Index}/{id?}");

            app.Run();
        }
    }
}

As you can see in the above code, currently, we have the route template pattern as {controller=Home}/{action=Index}/{id?}.

Generating Link Manually: We can generate the link manually using the following code by hard-coding the URL paths as /Home/Details.

<a href=”/Home/Details/@student.StudentId”>View</a>

Generating Link using Tag Helper: In the following code, we generate the link using anchor tag helper.

<a asp-controller=”Home” asp-action=”Details” asp-route-id=”@student.StudentId”>View</a>

As you can see with Tag Helper, we have not hardcoded the URL paths. Here, we only specify the controller and action name, route parameters, and their values. When the tag helpers are executed on the server, they automatically look at the route templates and generate the correct URLs.

Here, both the techniques generate the same URL path, i.e. (/Home/Details/101), and it also works with the current route template, i.e. ({controller=Home}/{action=Index}/{id?})

Now, let us change the routing template as shown below. Notice here the route template pattern. We have added the string literal “dotnet”.

Tag Helpers in ASP.NET Core MVC

So, with the above changes in place, manually generating the link will not work if you run the application, whereas the link generating with Tag Helpers will work as expected.

We also have tag helpers in ASP.NET Core to generate forms. When the form is posted back to the server, the posted form values are automatically handled, and the associated validation messages are displayed. Without these tag helpers, we would have to write many custom codes to achieve the same. Don’t worry if this is unclear now; we will discuss this with examples in our upcoming articles.

HTML Helpers vs. Tag Helpers in ASP.NET Core MVC:

In ASP.NET Core MVC, both HTML Helpers and Tag Helpers are mechanisms to assist developers in generating HTML markup within views. However, they have different approaches and characteristics. Let’s compare HTML Helpers and Tag Helpers to understand their differences and when to use each:

HTML Helpers:

HTML Helpers are methods provided by ASP.NET MVC that generate HTML markup using C# code directly within the Razor view files. They are essentially C# methods that return HTML strings and are used within Razor code blocks. HTML Helpers have been a part of ASP.NET MVC since its earlier versions.

Advantages of HTML Helpers:
  • Familiarity: Developers comfortable with C# coding can easily create dynamic HTML using HTML Helpers, as they involve standard C# coding practices.
  • Flexibility: HTML Helpers provide a high degree of control over the generated HTML since you’re working with C# directly. This can be advantageous when implementing complex logic within the view.
  • Fine-Grained Customization: You can customize the generated HTML in a very detailed manner by using HTML Helpers.
Disadvantages of HTML Helpers:
  • Readability: HTML Helpers can lead to less readable views, especially when the code is mixed with HTML markup and C# logic. This can make it harder for designers or front-end developers to understand the view’s structure.
  • Maintainability: The tight integration of C# code within the HTML markup can make views harder to maintain, as changes to the code can impact the overall structure of the view.
  • Separation of Concerns: HTML Helpers can sometimes blur the separation of concerns between the presentation (HTML) and the application logic (C#).
Tag Helpers:

Tag Helpers are a recent addition to ASP.NET Core MVC and provide a different approach to generating HTML markup. Tag Helpers allows developers to create custom HTML-like elements that encapsulate server-side logic, making the code more readable and separating concerns better.

Advantages of Tag Helpers:
  • Readability and Separation of Concerns: Tag Helpers improve the readability of views by resembling HTML markup and isolating server-side logic within custom tags. This promotes better separation of concerns between HTML structure and application logic.
  • Maintainability: Views written with Tag Helpers are generally more maintainable because the code is structured in a way that’s closer to standard HTML, making it easier for designers and front-end developers to collaborate.
  • Consistency: Tag Helpers allow you to create reusable components with consistent behavior across multiple views, reducing code duplication.
  • Tooling and IntelliSense: Tag Helpers provide better tooling support and IntelliSense in your IDE, helping developers to write code faster and with fewer errors.
Disadvantages of Tag Helpers:
  • Learning Curve: Developers familiar with C# and HTML might need time to adapt to the Tag Helper syntax.
  • Limited Flexibility: Tag Helpers might not offer the same level of fine-grained customization as HTML Helpers, especially for more complex scenarios.
When to Use Each:
  • HTML Helpers: Use HTML Helpers when you need fine-grained control over the generated HTML and when you’re comfortable working with C# code directly within your views. This might be more suitable for scenarios where complex logic needs to be embedded in the view.
  • Tag Helpers: Use Tag Helpers when prioritizing readability, maintainability, and separation of concerns. They are particularly useful for creating reusable UI components, improving collaboration between designers and developers, and creating clean and organized views.

In general, the choice between HTML Helpers and Tag Helpers depends on your team’s preferences, the level of customization required, and the emphasis you place on maintaining clean and maintainable views.

Advantages and Disadvantages of Tag Helpers in ASP.NET Core MVC

Tag Helpers in ASP.NET Core MVC are a feature that helps simplify the creation of dynamic and interactive HTML elements in your views. They provide a way to encapsulate server-side logic within HTML-like tags, making the code more readable and maintainable. However, like any technology, they come with their own set of advantages and disadvantages. Let’s explore them:

Advantages of Tag Helpers:
  • Readability and Intuitiveness: Tag Helpers use an HTML-like syntax, making the code more readable and intuitive, especially for front-end developers already familiar with HTML.
  • Separation of Concerns: Tag Helpers promote a cleaner separation of concerns by allowing you to keep UI logic and server-side code separate from your HTML markup
  • Code Reusability: Tag Helpers can be reused across different views, reducing code duplication and improving consistency. This is particularly beneficial when you have common UI components that require similar behavior across multiple views.
  • Enhanced IntelliSense and Tooling: Since Tag Helpers resemble HTML, you can use your IDE’s IntelliSense and other tooling features. This aids in faster development, as you get real-time suggestions and information about available attributes and properties.
  • Testing: Tag Helpers can be unit-tested to ensure they behave correctly and produce the expected output. This contributes to overall application stability and quality.
  • Easier to Learn: For developers familiar with HTML and Razor syntax, learning and using Tag Helpers is often more straightforward than other server-side programming techniques.
  • Encapsulation of Logic: Tag Helpers encapsulate server-side logic within the markup, reducing the need to mix Razor code directly with HTML elements.
  • Consistency: Tag Helpers help enforce consistent patterns for generating HTML elements throughout your application.
  • Flexibility: Tag Helpers can be extended and customized to match your specific requirements, providing high flexibility.
  • Automatic URL Generation: Tag Helpers automatically generate URLs for actions, controllers, and routes. This reduces the risk of broken links due to changes in your routing configuration.
  • Data Binding: Tag Helpers simplify data binding by automatically generating HTML attributes based on model properties. This helps prevent common security vulnerabilities like cross-site scripting (XSS).
  • Conditional Rendering: Tag Helpers enable conditional rendering of HTML elements based on server-side logic. This is valuable for showing or hiding elements dynamically.
  • Custom Tag Helpers: You can create custom Tag Helpers to encapsulate complex behaviors and improve reusability across your application.
Disadvantages of Tag Helpers:
  • Learning Curve: Developers already accustomed to traditional Razor syntax might need time to learn the new Tag Helper syntax and concepts.
  • Limited Customization: While Tag Helpers offer a more declarative approach, you might have less fine-grained control over the generated HTML than manually writing Razor code.
  • Performance Overhead: Tag Helpers introduce a small performance overhead due to the additional processing required to interpret and render the Tag Helper code. However, this overhead is generally minimal and might not be noticeable in most scenarios.
  • Limited Ecosystem: While the ecosystem of Tag Helpers has been growing steadily, it might not cover all possible scenarios or provide all the features you might need. In such cases, you might need to resort to other techniques or write custom Tag Helpers.
  • JavaScript Integration: For complex JavaScript-heavy interactions, integrating JavaScript libraries and custom code can be more challenging when using Tag Helpers.
  • Dependency on Framework: Using Tag Helpers ties your code more closely to the ASP.NET Core framework, potentially making it less portable to other platforms.
  • Potential for Overuse: Overusing Tag Helpers could lead to overly complex markup and excessive custom Tag Helpers.
  • Debugging Complexity: Debugging Tag Helpers might be slightly more complex due to the abstraction between markup and underlying logic.

The Tag Helpers in ASP.NET Core MVC offer several advantages regarding readability, maintainability, and separation of concerns. However, there might be a learning curve, and some trade-offs need to be considered, such as limited customization and potential performance overhead. It’s essential to evaluate your project’s requirements and the familiarity of your development team with these features before deciding whether to use Tag Helpers extensively.

Real-Time Use Cases of Tag Helpers in ASP.NET Core MVC:

Tag Helpers in ASP.NET Core MVC are versatile tools that provide a way to enhance the readability and maintainability of your views by encapsulating server-side logic within HTML-like tags. They are particularly useful when you want to integrate server-side functionality into your HTML markup seamlessly. Here are some common use cases for Tag Helpers:

  • Form Handling: Tag Helpers can simplify the process of creating forms and form elements. They can automatically generate the necessary HTML, handle validation messages, and bind form data to model properties.
  • Anchor Tags (Links): Tag Helpers can generate anchor tags (<a>) with URL parameters and route values, making it easier to create dynamic links within your views.
  • Image Rendering: Tag Helpers can be used to generate image tags (<img>) with dynamic URLs and alternate text. This is useful when displaying images stored on the server or from a content delivery network (CDN).
  • UI Components: You can use Tag Helpers to create reusable UI components, such as custom input fields, navigation menus, or cards. These components can encapsulate both visual presentation and associated server-side logic.
  • Bootstrap Integration: Tag Helpers can streamline the integration of popular CSS frameworks like Bootstrap. They can generate HTML elements with the appropriate CSS classes and attributes to ensure consistent styling.
  • Conditional Rendering: Tag Helpers can help conditionally render HTML elements based on specific conditions or data values. This is useful for displaying or hiding content dynamically.
  • Data Display: Tag Helpers can facilitate data display from models or databases. For example, you can use them to generate tables, lists, or other structured content based on your application’s data.
  • Pagination: Tag Helpers can assist in creating pagination controls, allowing users to navigate through a large set of data items.
  • Script and Style Tags: Tag Helpers can generate script (<script>) and style (<link>) tags with dynamic URLs, enabling better management of JavaScript and CSS resources.
  • Meta Tags: Tag Helpers can generate meta tags for specifying metadata about a web page, such as title, description, and keywords.
  • Localization: Tag Helpers can help with localization by generating appropriate HTML tags for displaying content in different languages or cultures.
  • Security: Tag Helpers can be used to generate anti-forgery tokens and other security-related elements that help protect your application from common web vulnerabilities.

These are just a few examples of how Tag Helpers can be applied in ASP.NET Core MVC. The key advantage of Tag Helpers is that they provide a natural and intuitive way to incorporate server-side logic within your HTML markup, making your views more maintainable and readable while promoting the separation of concerns.

When to use Tag Helpers in ASP.NET Core MVC?

Tag Helpers in ASP.NET Core MVC are a powerful tool, but knowing when to use them requires understanding their benefits and the scenarios where they shine. Here are some situations where using Tag Helpers can be particularly beneficial:

  • Generating URLs: Tag Helpers are great for generating URLs for actions and controllers. Instead of manually constructing URLs in your views, you can use Tag Helpers to ensure URLs are generated correctly based on routing and route parameters.
  • Form Generation: Tag Helpers simplify the process of generating HTML forms. They automatically set the correct action and method attributes based on the specified controller and action.
  • Conditional Attributes: When you need to add attributes to HTML elements based on certain conditions conditionally, Tag Helpers can make your code more readable by incorporating the logic directly into the markup.
  • HTML Encapsulation: Tag Helpers help encapsulate complex UI logic, allowing you to create reusable UI components that can be easily reused across multiple views.
  • Intuitive Integration of Server-Side Logic: Tag Helpers provide a more intuitive way to integrate server-side logic into your views. This results in cleaner and more maintainable code than mixing traditional HTML with embedded Razor code.
  • Custom UI Components: Tag Helpers can encapsulate the visual markup and any required backend logic when creating custom UI components or widgets.
  • Consistency: Tag Helpers can help enforce a consistent approach to generating HTML elements and ensure that best practices are followed throughout your application.
  • Data Binding: When you need to bind data from your model to HTML attributes, Tag Helpers simplify the process. They help ensure your data is properly escaped and formatted in the generated HTML.
  • Complex HTML Elements: Tag Helpers can significantly enhance readability for complex HTML elements like forms. They make it easier to include various attributes, such as method and action, while also handling data binding for form fields.

However, there are situations where using traditional Razor syntax or HTML helpers might be more appropriate:

  • Simple Markup: Using regular HTML might be sufficient and more straightforward for simple HTML elements without much dynamic behavior.
  • JavaScript-Heavy Interactions: If you’re dealing with complex client-side interactions or JavaScript-heavy components, you might still need to rely on traditional HTML combined with JavaScript libraries.
  • Familiarity: If your development team is more comfortable with traditional Razor syntax, switching to Tag Helpers is not required.
  • Inline Expressions: Traditional Razor syntax might be more concise and readable for simple, one-liner expressions.
  • Non-HTML Markup: If you’re generating content that isn’t HTML, such as JSON or JavaScript, traditional Razor syntax might be more appropriate.
  • Existing Codebase: If you’re working with an existing codebase that heavily uses traditional Razor syntax, it might be more consistent to continue using it.

Consider using Tag Helpers when creating more readable, maintainable, and reusable views, especially for scenarios involving URLs, forms, and custom UI components. The decision to use Tag Helpers should align with your project’s specific needs and goals.

In the next article, I will discuss the Image Tag Helper in ASP.NET Core MVC Application. In this article, I try to explain the basics of Tag Helpers in ASP.NET Core MVC Application with examples. I hope you enjoy this article.

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