C# 4 and .NET 4

Control Class ❘ 1123
the Control class. Later in the chapter, when you look at the specific controls based on the Control class,
you will see the properties and methods in some sample code. The following subsections group the methods
and properties by functionality, so related items can be looked at together.
size and location
The size and location of a control are determined by the properties Height, Width, Top, Bottom, Left,
and Right along with the complementary properties Size and Location. The difference is that Height,
Width, Top, Bottom, Left, and Right all take single integers as their value. Size takes a Size structure
and Location takes a Point structure as their values. The Size and Point structures are a contained
version of X,Y coordinates. Point generally relates to a location and Size is the height and width of an
object. Size and Point are in the System.Drawing namespace. Both are very similar in that they provide
an X,Y coordinate pair but also have overridden operators for easy comparison and conversion. You can,
for example, add two Size structures together. In the case of the Point structure, the Addition operator
is overridden so that you can add a Size structure to a Point and get a new Point in return. This has
the effect of adding distance to a location and getting a new location. This is very handy if you have to
dynamically create forms or controls.
The Bounds property returns a Rectangle object that represents the area of a control. This area includes
scroll bars and title bars. Rectangle is also part of the System.Drawing namespace. The ClientSize
property is a Size structure that represents the client area of the control, minus the scroll bars and title bar.
The PointToClient and PointToScreen methods are handy conversion methods that take a Point and
return a Point. PointToClient takes a Point that represents screen coordinates and translates it to
coordinates based on the current client object. This is handy for drag-and-drop actions. PointToScreen
does just the opposite — it takes coordinates of a client object and translates them to screen coordinates.
The RectangleToScreen and ScreenToRectangle methods perform the same functionality with
Rectangle structures instead of Points.
The Dock property determines which edge of the parent control the control will be docked to. A DockStyle
enumeration value is used as the property’s value. This value can be Top, Bottom, Right, Left, Fill, or
None. Fill sets the control’s size to match the client area of the parent control.
The Anchor property anchors an edge of the control to the edge of the parent control. This is different from
docking in that it does not set the edge to the parent control but sets the current distance from the edge so
that it is constant. For example, if you anchor the right edge of the control to the right edge of the parent
and the parent is resized, the right edge of the control will maintain the same distance from the parent’s
right edge. The Anchor property takes a value of the AnchorStyles enumeration. The values are Top,
Bottom, Left, Right, and None. By setting the values, you can make the control resize dynamically with the
parent as the parent is resized. This way, buttons and text boxes will not be cut off or hidden as the form is
resized by the user.
The Dock and Anchor properties used in conjunction with the Flow and Table layout controls (discussed
later in this chapter) enable you to create very sophisticated user windows. Window resizing can be difficult
with complex forms with many controls. These tools help make that process much easier.
appearance
Properties that relate to the appearance of the control are BackColor and ForeColor, which take a
System.Drawing.Color object as a value. The BackGroundImage property takes an Image-based object as
a value. The System.Drawing.Image class is an abstract class that is used as the base for the Bitmap and
Metafile classes. The BackgroundImageLayout property uses the ImageLayout enumeration to set how
the image is displayed on the control. Valid values are Center, Tile, Stretch, Zoom, and None.
The Font and Text properties deal with displaying the written word. In order to change the Font you will
need to create a Font object. When you create the Font object, you specify the font name, size, and style.
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