Tag helpers are a feature in ASP.NET Core MVC that allow you to extend HTML elements with server-side capabilities. They are C# classes that modify the behavior and output of HTML elements during the rendering process.
Advantages HTML-Friendly Syntax: Tag helpers look like standard HTML elements, making them easier to read and write than traditional HTML helpers. Strong Typing: Tag helpers offer compile-time type safety and IntelliSense support, catching errors early in development. Code Reuse: They can be easily reused across different views and projects. Reduced Server Roundtrips: Tag helpers execute on the server, allowing you to perform complex logic and data binding before the page is sent to the client. Extensibility: You can create your own custom tag helpers to meet specific needs.
Namespace : Tag helper namespaces organized (e.g., @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers).
Disadvantages Overusing Tag Helpers: Use them for appropriate tasks, not for every HTML element. Excessive Nesting: Avoid deeply nested tag helpers, as it can make your code difficult to read. Mixing Tag Helpers and HTML Helpers: Try to use either tag helpers or HTML helpers consistently within a view to maintain a cleaner code structure.
Examples :- Anchor Tag Helper (<a>): <a asp-controller=”Home” asp-action=”Index”>Home</a> Generates a link to the Index action method in the HomeController. Automatically handles routing and URL generation.
Form Tag Helper (<form>): <form asp-controller=”Tools” asp-action=”Create” method=”post”> </form> Creates a form that submits data to the Create action in the ToolsController. Handles anti-forgery tokens automatically for better security.
Input Tag Helper (<input>): <input asp-for=”ToolName” class=”form-control” /> Binds the input field to the ToolName property of your model. Automatically sets the input type (e.g., text, email, password) based on the property type.
Select Tag Helper (<select>): <select asp-for=”CatId” asp-items=”Model.Cats”></select> Creates a dropdown list bound to the CatId property. asp-items takes a collection of items to populate the dropdown.
Label Tag Helper (<label>): <label asp-for=”ToolName”></label> Generates a label for the ToolName input field, automatically setting the for attribute to match the input’s ID.
Cache Tag Helper (<cache>): <cache expires-after=”@TimeSpan.FromMinutes(10)”> Content to cache </cache> Caches the enclosed content for the specified duration. Improves performance for content that doesn’t change frequently.
Environment Tag Helper (<environment>):
<link rel=”stylesheet” href=”~/css/site.css” asp-append-version=”true” /> The asp-append-version attribute automatically adds a version query string to the URL in non-development environments, which helps with cache busting when you deploy updates.
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