.NET Windows Forms in a Nutshell

Layout

As we saw in the previous chapter, the framework can modify a control’s position and size automatically. We looked at the docking and anchoring facilities, but Windows Forms provides support for other styles of layout. The simplest of these is a fixed layout in a scrollable window. Splitter support is also built in. In this section, we will look at all these styles of layout, and then examine the mechanism in the framework that underpins them all. It is possible to extend the layout facilities to provide your own automatic layout strategies. We will look at the standard events that support this, and then see a simple example custom layout engine.

Scrolling

Windows Forms provides a facility for enabling the contents of a control to exceed the control’s size on screen, and for scrollbars to be added automatically to enable the user to access all of it. This functionality is provided by the ScrollableControl class. This is the base class of ContainerControl and of Panel, which means that this behavior is available to all forms, panels, and user controls.

To enable automatic scrolling management, simply set the AutoScroll property to true. If the window is smaller than its contents, scrollbars will be added automatically. Of course, the class will need some way of knowing how large the window’s contents are. By default, it will deduce this from its child controls—it will assume that the window’s size should be exactly large enough to hold all the controls.

Because automatic ...