Programming .NET Windows Applications

SystemInformation Properties

Strictly speaking, it is not necessary to have a mouse or other pointing device installed on a Windows system, although as a practical matter, it is difficult to work with Windows without one, and virtually every modern Windows computer has a mouse or pointer installed. The SystemInformation class provides several read-only static (Shared in VB.NET) properties, listed in Table 8-1, which allow a program to determine if a mouse is connected to the system, and if so, the configuration and capabilities of the mouse. Accessing these properties is demonstrated in the programs listed in Example 8-1 (in C#) and in Example 8-2 (in VB.NET).

Most mice in use today on Windows systems have two buttons: the left button is typically the primary button and the right button is typically the secondary button. The user can swap these preferences in the Control Panel/Mouse applet to allow left-handed users to reverse the buttons. If the primary button is clicked twice in rapid succession without moving more than a certain number of pixels, the action is interpreted as a double-click. Many mice today also have a mouse wheel, which can also be seen by the system as a third button. The last three properties listed in Table 8-1 relate to the wheel.

Table 8-1. SystemInformation mouse properties

Property	Type	Description
DoubleClickSize	Size	Returns dimensions, in pixels, of rectangular area around the first mouse click within which two mouse clicks can be considered a double-click. ...