Handling Input on Windows Phone 7 : The Keyboard

1. Physical Keyboard

Windows Phone 7 devices may also have a hardware slide-out keyboard, but your application will not pass certification in App Hub if it is dependent upon the hardware keyboard. Otherwise, from a software development perspective, programming for hardware keyboard input "just works." Of the six devices available at Windows Phone 7 launch, only one had a full slide-out keyboard, and another had a vertical QWERTY keyboard. The other four devices were pure touch devices without a physical keyboard.

2. Soft Input Panel (SIP) Keyboard

All Windows Phone 7 devices have a SIP keyboard used for entering text. Typing on the SIP keyboard built into Windows Phone 7 is a pretty comfortable means of entering text; however, it is still a small keyboard, so anything that a developer can do to ease typing can really help improve the overall user experience.

3. Programming with the Keyboard

Typing text on a mobile phone should be minimized as much as possible, but if text input is required, a developer should take advantage of capabilities to make typing as simple as possible. In the next section I cover InputScope, which is a must-have feature to take advantage of when typing is required in your Windows Phone 7 applications.

When testing keyboard input, you will be tempted to type on your PC keyboard; however, it does not work. You must use the mouse with the SIP keyboard in the Emulator for input.

3.1. InputScope

The InputScope property is available on the TextBox control, which is the primary control for text input. InputScope lets the developer customize the keyboard for the expected type of input. For example, the default behavior is that when you click into a TextBox, the SIP keyboard pops up, as shown in Figure 1.

Figure 1. Default SIP keyboard

The second TextBox has an InputScope of Text, which enables word selection just above the keyboard, as shown in Figure 2.

Figure 2. InputScope of Text SIP keyboard with word suggestion

With just one simple attribute, text input becomes much easier for the enduser. Figure 3 shows three additional text input options, which I explain just after the figure.

Figure 3. Search, Password, and TelephoneNumber InputScopecustomizations

Configuring an InputScope of Search turns the Enter key into a GO key with the idea that the user enters a search keyword and then clicks Enter to kick off a search. Password is not actually an InputScope. It is a custom TextBox class named PasswordBox that automatically hides data entry as the user types. An InputScope of TelephoneNumber brings up a phone keypad. As you can see, all of these could come in handy as you develop your application UI and optimize input for the end user. Table 1 lists the available InputScope options and their descriptions, reprinted here for your convenience from the Windows Phone 7 documentation.

Let's now shift gears and explore the available keyboard events.

3.2. Keyboard Events

There are two keyboard events available on the TextBox, as well as pretty much any other object that inherits from UIElement: the KeyDown and KeyUp events. Both events have a KeyEventArgs class in its parameters that provides access to the Key and PlatformKeyCode values native to the platform. It also provides access to the OriginalSource property that represents the control that raised the Keyboard event, as well as a Handled member to indicate that the key has been processed.

This completes our discussion of keyboard events. In general, typing should be minimized in a mobile application for the reasons listed previously, i.e., small screen, small keyboard, and so on. Mobile devices are optimized for touch input, especially modern devices with highly responsive capacitive touch screens that do not require a stylus. Let's now focus on touch input.