ASP.NET Core  

From Server Controls to Tag Helpers in ASP.NET Core – A Complete Guide with Examples

Below is a complete, ready-to-publish blog article explaining Server Controls → Tag Helpers in ASP.NET Core with clear examples.

In classic ASP.NET WebForms, developers used Server Controls (<asp:TextBox>, <asp:GridView>, <asp:Button>, etc.) to create UI elements. These controls were powerful but also had limitations — they generated heavy HTML, relied on ViewState, and provided less control over the rendered output.

ASP.NET Core introduced Tag Helpers, a modern way to generate dynamic HTML using natural HTML tags enriched with server-side features.

This blog explains:

  • What Server Controls were

  • What Tag Helpers are

  • Why Tag Helpers are better

  • How to replace Server Controls with Tag Helpers

  • Real examples

1. What Were Server Controls in ASP.NET WebForms?

Server controls were UI components that ran on the server and automatically generated HTML.

Examples

<asp:TextBox ID="txtName" runat="server" />
<asp:Button ID="btnSave" Text="Save" runat="server" OnClick="btnSave_Click" />

They supported:

  • Auto events (Click, Load, Init...)

  • Auto-binding

  • ViewState (to maintain values)

  • Drag-and-drop programming

But they also had major drawbacks:

1. Heavy ViewState
2.Hard-to-control HTML output
3.Hard to optimize performance
4.Not suitable for modern JavaScript frameworks
5.Tight coupling with WebForms lifecycle

2. ASP.NET Core MVC Replacement → Tag Helpers

Tag Helpers allow you to write clean HTML and still use server-side code.

Example

<input asp-for="Name" class="form-control" />
<button asp-action="Save" class="btn btn-success">Save</button>

They look like normal HTML, but ASP.NET Core injects server-side functionality.

3. Why Tag Helpers Are Better Than Server Controls

  1. Clean and readable HTML

  2. No ViewState (faster pages)

  3. SEO-friendly

  4. Works smoothly with modern front-end frameworks

  5. Easy to customize

  6. Strongly typed with model binding

4. How to Enable Tag Helpers

Inside _ViewImports.cshtml:

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

This activates built-in Tag Helpers across all Razor views.

5. Replacing Server Controls with Tag Helpers (With Examples)

5.1 TextBox Control → Input Tag Helper

WebForms

<asp:TextBox ID="txtEmail" runat="server"></asp:TextBox>

ASP.NET Core MVC

Model:

public string Email { get; set; }

View:

<input asp-for="Email" class="form-control" />
<span asp-validation-for="Email"></span>

Benefits:

  • Strongly typed

  • Works with validation

  • Cleaner HTML

5.2 Button Control → Form Action Tag Helper

WebForms

<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />

ASP.NET Core MVC

Controller:

[HttpPost]
public IActionResult Submit(FormModel model)
{
    // handle data
    return View();
}

View:

<form asp-action="Submit">
    <button type="submit" class="btn btn-primary">Submit</button>
</form>

Pure HTML
No server-side events, only HTTP methods (GET/POST)

5.3 DropDownList Control → Select Tag Helper

WebForms

<asp:DropDownList ID="ddlCity" runat="server"></asp:DropDownList>

ASP.NET Core MVC

Model:

public string City { get; set; }
public List<SelectListItem> Cities { get; set; }

Controller:

public IActionResult Index()
{
    var model = new FormModel
    {
        Cities = new List<SelectListItem>
        {
            new SelectListItem{ Text="Chennai", Value="Chennai"},
            new SelectListItem{ Text="Bangalore", Value="Bangalore"}
        }
    };
    return View(model);
}

View:

<select asp-for="City" asp-items="Model.Cities" class="form-select"></select>

Much simpler
Strongly typed
Clean markup

5.4 GridView Control → Table + Model Binding

WebForms

<asp:GridView ID="GridEmployees" runat="server"></asp:GridView>

ASP.NET Core MVC

Controller:

public IActionResult List()
{
    var employees = new List<Employee>
    {
        new Employee{Id=1, Name="John"},
        new Employee{Id=2, Name="Emma"}
    };
    return View(employees);
}

View:

<table class="table table-striped">
    <thead>
        <tr><th>ID</th><th>Name</th></tr>
    </thead>
    <tbody>
    @foreach(var emp in Model)
    {
        <tr>
            <td>@emp.Id</td>
            <td>@emp.Name</td>
        </tr>
    }
    </tbody>
</table>

Full control over HTML
No hidden styling or generated markup
Easy to customize

Conclusion

Moving from Server Controls to Tag Helpers in ASP.NET Core MVC gives developers:

  • More control

  • Better performance

  • Cleaner HTML

  • Strong type safety

  • Modern web standards

While WebForms relied heavily on server-side controls and ViewState, ASP.NET Core MVC embraces lightweight HTML with server-side Razor support through Tag Helpers.

If you're transitioning from WebForms or learning ASP.NET Core, mastering Tag Helpers is essential for building clean, maintainable, and high-performance web applications.

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