I have heard lots of complaining about how difficult is custom control programming. It can be really easy and productive. You can use same simple control in different pages easily. This post assumes that you have basic understanding about Visual Studio and ASP.Net programming.

Creating projects

Steps:

1. Create Web Site.
   You can use Web Site or Web Application project. It makes no difference in this demo.
2. Create Class Library project.
3. Add Class Libray reference to web site.
4. Add System.Web reference to Class Library projec

I always use different project for custom controls.

Programming a control

Steps:

1. Create a new class.
2. Add additional usings.
   using System.Web.UI;
   using System.Web.UI.WebControls;
3. Add base class for your component.
   public class Posting : Panel
4. Create a new property called Title.
   public string Title { get; set; }
5. Override RenderBeginTag.
   public override void RenderBeginTag(HtmlTextWriter writer)
6. Add custom rendering code.
   writer.WriteLine("<div class=\"post\">");
   writer.WriteLine("<h2 class=\"title\">{0}</h2>", Title);
   writer.WriteLine("<div class=\"entry\">");
7. Override RenderEndTag.
   public override void RenderEndTag(HtmlTextWriter writer)
8. Add custom rendering code.
   writer.WriteLine("</div>");
   writer.WriteLine("</div>");

Using custom control on page