The Control object defines a Text property that is used by derived controls for a variety of purposes. For a text box, the Text property corresponds to the information displayed in the text box, which can be modified by the user. For controls like labels, command buttons, or forms, the Text property refers to static descriptive text displayed as a title or caption.
The font of a control's text is defined by the Font property, which uses an instance of the System.Drawing.Font class. Note that a Font object does not just represent a typeface (like Tahoma). Instead, it encapsulates all details about the font family, point size, and styles (like bold and italic).
// You can create a font with one of the 13 constructors.
ctrl.Font = new Font("Tahoma", 8, FontStyle.Bold);
A traditional default font for Windows programs is often Microsoft Sans Serif. However, newer applications since Windows 98 consistently use the slightly more attractive Tahoma font (which is also better for input, as it distinguishes between characters like a lowercase "l" and uppercase "I").You should use the Tahoma font in your applications.
A Control.FontHeight property is also provided, which returns the height of your chosen font in pixels. This setting allows you to perform calculations when you are drawing special graphics or text on a control manually. For example, you could manually space lines the appropriate amount when drawing text directly onto a form background.
Note that font families are set using a string, rather than a type-safe enumerated property. If you try to create an object using a name that does not correspond to an installed font, .NET automatically (and unhelpfully) defaults to the Microsoft Sans Serif font. An error does not occur. You may want to explicitly check the Font.Name property to check if this automatic substitution has been made.
To determine what fonts are installed on the system, you can enumerate through them with the System.Drawing.Text.InstalledFontCollection class. The example below adds the name of every installed font to a list box.
InstalledFontCollection fonts = new InstalledFontCollection();
foreach (FontFamily family in fonts.Families)
{
lstAvailableFonts.Add(family.Name);
}
The online samples for this chapter include a FontViewer utility that uses this technique to create a list of fonts. The user can choose a font from a drop-down list control, and a sample line of text will be painted directly on the window (see Figure 3-5). To perform the font painting, the application uses some of the GDI+ methods you'll see in Chapter 12.
Figure 3-5: A simple font viewer
Note that the Font property does not always configure the appearance of the text in the control. For example, the font of all windows is defined by the system and is unchangeable. Instead, the Form.Font property defines the default font for all contained controls.
Some controls (namely buttons and menu items) allow a character in their caption to be highlighted and used as an access key. For example, button controls often underline one character in the caption. If the user presses the Ctrl key and that character, the button is "clicked" automatically. To configure these shortcuts keys just add an ampersand (&) before the special letter, as in "Sa&ve" to make "v" the access key. (If you actually want to use an ampersand, you'll need to include the text "&&".)