Programming WPF, 2nd Edition

Canvas

Occasionally, it can be necessary to take complete control of the precise positioning of every element. For example, when you want to build an image out of graphical elements, the positioning of the elements is dictated by the picture you are creating, not by any set of automated layout rules. For these scenarios, you can use a Canvas.

Canvas is the simplest of the panels. It allows the location of child elements to be specified precisely relative to the edges of the canvas. The Canvas doesn't really do any layout at all; it simply puts things where you tell it to. Also, Canvas will not size elements to fill the available space—all its children are sized to content.

Warning

If you are accustomed to working with fixed layout systems such as those offered by Visual Basic 6, MFC, and the most basic way of using Windows Forms, the Canvas will seem familiar and natural. However, it is strongly recommended that you avoid it unless you really need this absolute control. The automatic layout provided by the other panels will make your life much easier because they can adapt to changes in text and font. They also make it far simpler to produce resizable user interfaces. Moreover, localization tends to be much easier with resizable user interfaces, because different languages tend to produce strings with substantially different lengths. Don't opt for the Canvas simply because it seems familiar.

When using a Canvas, you must specify the location of each child element. If you don't, all ...