Understanding Text Element Types

Within the Windows Phone Framework Class Library (FCL), there are some types, which, on first appearance, you could be forgiven for thinking that API similarities are the result of common ancestry. The TextBlock and TextBox elements, for example, have numerous similarly named text and font related properties, yet both have their own distinct API and their closest ancestor is FrameworkElement (see Figure 6.1).

FIGURE 6.1 Text related framework elements.

The TextBox and PasswordBox are derived from the System.Windows.Control class. The Control class is the base class for UI elements that use a ControlTemplate to define their appearance. And while the TextBlock lives in the System.Controls namespace, it is not a Control, making it impossible to drastically change its appearance. Those familiar with WPF will know that WPF has the Label class, which is derived from Control and which fills this gap. There is, however, no such control in the Windows Phone SDK.

The similarities between the TextBlock and TextBox APIs do mean, however, that the elements can be styled in much the same manner; the characteristics of most font and layout related properties apply equally to all three text elements.