Quite often it’s desirable to group related content and controls. You can do this by putting the
controls (and other markup) in one of the container controls, like the Panel, the PlaceHolder, the MultiView, or the Wizard. For example, you can use the PlaceHolder or the Panel control to hide or show a number of controls at once. Instead of hiding each control separately, you simply hide the entire container that contains all the individual controls and markup. Both of these controls have their own advantages and disadvantages. The good thing about the PlaceHolder control is that it emits no HTML of its own into the page, so you can use it as a container without any side effects in the final page. However, it lacks design-time support, making it hard to manage the controls inside the PlaceHolder at design time in VS. In contrast, the Panel enables you to easily access all controls and other content it contains but renders itself as a element. In many cases this isn’t a problem, and can even be useful as you can target that div using CSS at the client, so usually you’re best off with the Panel control because of its design-time support. The MultiView (which can contain one or more elements) and the Wizard are similar in that they enable you to split up a long page into multiple areas, making it easy to fill in a long form, for example. The Wizard has built-in support for moving from page to page using Previous,Next, and Finish buttons, whereas the MultiView must be controlled programmatically.A Closer Look at the Panel Control In the following exercise, you use a Panel control to create a container for other controls and markup. You only add some text for now, but in a subsequent Try It Out exercise you add ASP.NET controls to the panel.