Set style attributes : Style « Controls « ASP.NET Tutorial

<%@ Page Language="C#" 
         Inherits="StyleAttributes" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "">

<html xmlns="" >
<head runat="server">
    <title>Untitled Page</title>
    <form id="form1" runat="server">
        <input id="TextBox1" runat="server" type="text" /></div>

File: Default.aspx.cs

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class StyleAttributes : System.Web.UI.Page
  protected void Page_Load(object sender, System.EventArgs e)
    if (!Page.IsPostBack)
      TextBox1.Style["font-size"] = "20px";
      TextBox1.Style["color"] = "red";

      TextBox1.Style.Add("background-color", "lightyellow");

      TextBox1.Value = "<Enter e-mail address here>";

      TextBox1.Attributes["onfocus"] = "alert(TextBox1.value)";


3.34.1.Test the border properties
3.34.2.set background color programmatically
3.34.3.This is a test of the color properties
3.34.4.Bold font
3.34.5.Working with the Font properties: Font-Italic, Font-Names,Font-Size
3.34.6.Set style attributes
3.34.7.Css style
3.34.8.Using style
3.34.9.Style server control
3.34.10.Font change