"Pro ASP.NET 3.5 Server Controls and AJAX Components"
AddAttribute("value",Text); Now that we have covered the basics of inheriting from WebControl, we can move on to add style capabilities to our TextBox control from earlier in this book. A Styled TextBox Control In this section, we bring back our favorite TextBox control from chapters past and update it with WebControl capabilities. As you would guess, most of the implementation remains the same. The biggest changes relate to how we handle the rendering process. CHAPTER 4 ?– THE WEBCONTROL BASE C LASS AND CONTROL STYLES 137 The first step in updating TextBox is to inherit from WebControl and set the constructor to create the tag for the outer shell of the control. The following code snippet sets up our WebControl version of the TextBox to render an tag: public class Textbox : WebControl, IPostBackDataHandler { public Textbox() : base(HtmlTextWriterTag.Input) { } } The rendering code in this version of TextBox is dramatically smaller than the previous version that inherited from Control. All we have to implement is the AddAttributesToRender() method to set the tag with the appropriate attributes, and we need to call the base class version to add the style properties: override protected void AddAttributesToRender(HtmlTextWriter writer) { writer.