ASP.NET Server Controls Explained – Button, TextBox, GridView | BCA Sem 5

BCA Sem 5  |  Unit 1  |  ASP.NET

Types of Controls in ASP.NET

Buttons, textboxes, dropdowns & more — the building blocks of every web form

BKNMU Junagadh NEP 2020 Web Forms Server Controls

In simple words: Controls are the building blocks of an ASP.NET web page — things like buttons, textboxes, checkboxes, and dropdowns. Instead of writing plain HTML, ASP.NET gives you ready-made "smart" controls that run code on the server and remember their values automatically.

📖 What are Controls in ASP.NET?

A control is simply a UI element you place on a web page — like a textbox to type your name, or a button to submit a form. In ASP.NET, these controls are written using <asp:ControlName> tags and have the special attribute runat="server", which tells ASP.NET to process them on the server, not just the browser.

📦 Four Main Categories of Controls

🟪 HTML Controls

Plain HTML elements without runat="server". Processed only by the browser, not the server.

🟦 HTML Server Controls

HTML elements with runat="server" added — now ASP.NET can access them in code-behind.

🟩 Web Server Controls

ASP.NET's own rich controls like <asp:Button>, <asp:GridView> — most commonly used.

🟧 Validation Controls

Special controls that check user input — like RequiredFieldValidator, RangeValidator.

ℹ️ Most Used in Practice: Web Server Controls are what you'll use 90% of the time in ASP.NET Web Forms — they are powerful, have rich properties, and automatically maintain ViewState.

🎨 Standard Controls — Visual Showcase

<asp:Button> Triggers a postback or runs a server-side action on click.

Submit

<asp:TextBox> Lets users type and submit text input.

<asp:CheckBox> A simple true/false toggle option.

I agree to terms

<asp:Label> Displays read-only text, often updated dynamically.

Welcome, Student!

<asp:Panel> A container to group and show/hide multiple controls together.

Panel Container (groups controls)

<asp:ListBox> Shows a scrollable list where users can select one or more items.

BCAMCABBA

<asp:DropDownList> A collapsible dropdown for choosing a single option.

Select Course ▾

<asp:FileUpload> Allows users to select and upload a file to the server.

📎 Choose File — no file selected

<asp:AdRotator> Displays rotating banner advertisements from an XML file.

🖼️ Ad Banner #1 of N (rotates)

<asp:CheckBoxList> A group of checkboxes generated from a data source.

HTML

CSS

ASP.NET

<asp:RadioButtonList> Lets the user pick exactly one choice from a group.

Male Female

<asp:ImageMap> An image with multiple clickable regions, each posting back separately.

🗺️ Clickable Image Regions

<asp:Wizard> Breaks a long form into multiple steps with Next/Back navigation.

Step 1 ● → Step 2 ○ → Step 3 ○

<asp:Calendar> A full month calendar control to select dates easily.

S

M

T

W

T

F

S

1

2

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<asp:GridView> Displays tabular data — most used control for showing database records.

ID	Name
1	Raj
2	Asha

✅ What is Validation? (Quick Intro)

Validation means checking whether user input is correct before processing it — for example, making sure an email field isn't empty, or a number is within range. ASP.NET makes this easy with built-in Validation Controls.

🌐 Client-Side Validation

Checked instantly in the browser using JavaScript — fast, no server round-trip needed.

🖧 Server-Side Validation

Checked on the server after submission — more secure, can't be bypassed by disabling JS.

Validator	What It Checks
RequiredFieldValidator	Ensures the field is not left empty
RangeValidator	Checks if value falls within a min-max range
CompareFieldValidator	Compares two fields (e.g. Password & Confirm Password)
RegularExpressionValidator	Checks input against a pattern (e.g. valid email format)
CustomValidator	Runs your own custom validation logic
ValidationSummary	Shows a summary list of all validation errors on the page

💻 Code Example — Using Controls Together

<asp:TextBox ID="txtEmail" runat="server" /> <asp:RequiredFieldValidator runat="server" ControlToValidate="txtEmail" ErrorMessage="Email is required!" /> <asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />

💡 Tip: Every Web Server Control must have runat="server" — without it, ASP.NET treats it as plain HTML and you can't access it from your C# code-behind!

📝 Quick Revision — Key Points for Exam

• Controls = UI building blocks of an ASP.NET page (buttons, textboxes, etc.).
• 4 categories: HTML Controls, HTML Server Controls, Web Server Controls, Validation Controls.
• runat="server" is required for any control to be processed on the server.
• Common controls: Button, TextBox, CheckBox, Label, Panel, ListBox, DropDownList.
• Special controls: FileUpload, AdRotator, CheckBoxList, RadioButtonList, ImageMap, Wizard, Calendar.
• Validation = checking user input before processing it.
• Client-side validation runs in browser (JS) — Server-side runs on server (secure).
• 6 main validators: RequiredField, Range, CompareField, RegularExpression, Custom, ValidationSummary.