Top
10 UI Development Breakthroughs in Windows Presentation Foundation
The
graphics system that is used currently in the Win32 subsystems is constrained
whereas the graphics system in the Windows Presentation Foundation is
based on the .Net Framework. Hence it considers the latest technologies
and the latest hardware available. There are many improvements in the
User Interface that is achieved by the WPF. Some of them are discussed
in this article.
Declarative Programming
Declarative
programming is defining what we want instead of defining how. Example
for declarative programming is SQL statements. In SQL statement we define
what data we want, and the database engine take care of how to fetch the
data.
It is easy
to write code in declarative programming. The maintenance of programs
with declaration statement is easier, because the intent of the code is
clear to understand. The length of the code becomes less.
Below is the sample code for declaring grid for UI
Style is nothing but a named set of attributes and values. This can be
applied to any elements in the UI like buttons, templates etc. Style provides
useful mechanism for setting look and feel of controls, without affecting
control's structure or behavior.
In the previous
example a style can be set for a button, when a mouse was moved over button.
The style
can be stored in resource file and can be applied individual or all controls
of particular type.
Data driven
UI
The main
advantage of WPF is that most controls can contain any type of contents.
For example button controls can have panel, which intern include visual
objects like ellipse and/or buttons.
This is achieved
by a mechanism called Data Template. It tells the WPF, how to display
an object.
Data template
can be set for particular control or set for a context, in this case all
the controls which uses a particular type of objects uses that template
to form the display.
Lookless
control
In the current
windows GUI technologies, each control have to of particular shape and
border, but in WPF this is not the case. Most of the controls do not have
any shape attached to it. They attach to shape defined externally in a
template.
So in designing
GUI, we should think about functionality to be achieved, and accordingly
we have to select controls.
Flexible
content model
In WPF, most
of the controls can display anything in the content area. There is no
restriction that is should be only text or bitmap.
For example,
a button control can display a panel with shape objects like ellipse.
If we use current technologies, then we need to override draw method with
lot of effort.
In WPF, this kind designing controls can be done by designers, after getting
requirement from the programmer.
Adaptable
UI Layout
Layout comes
to picture, when the developer doesn't know the size the application window.
One user may run the application with window maximized and another can
title more number of windows. In these case the controls inside the application
window should readjust them self for maximum usability/easiness.
There are
different kinds of layout available, like flow layout, grid layout etc.
The mostly used and powerful layout is grid layout. In WPF developer can
use existing layout or they can define their own. Mechanism available
for adaptive layout are docking and anchoring.
Rich Fonts
for Texts
The WPF support
rich text formatting. A control text can have characters of different
fonts. A word documents can embed controls in between the characters.
The below
example shows the method of formatting a text using XAML
<TextBlock
FontFamily="Calibri" FontSize="11pt">
Hello, <Bold>world!</Bold>
<Span FontFamily="Old English Text MT"
FontSize="24pt">This</Span>
is a
<Italic>single</Italic>
<Span FontFamily="Consolas" Foreground="Blue">
<<Span Foreground="DarkRed">TextBlock</Span>/>
</Span>
<Hyperlink>element</Hyperlink>.
</TextBlock>
Drawing
object Model
In the previous
version of Windows Technology, drawing a control is set of operation.
In WPF, it is collection of object. The controls contain collection of
elements like line and circle. When you change a property of an object,
it automatically get reflected in the screen. There is no need to call
redraw or invalidate methods explicitly.
This approach
is much easier than the previous approaches, which uses USER32 and GDI+.
Advanced
Graphics
Other new
features of WPF are:
1. Enhanced
drawing capabilities
The WPF allows modifying the opacity of any content.
2. Fewer
control constraints
The controls can be drawn transparent. It is possible to visualize the
control beneath a control because in WPF all controls are drawn one above
the other, so each pixel is drawn multiple times, so that is possible
have the effect of 3 dimensions.
3. Resolution
independent
It is possible to scale the Graphics objects in side an application window
as a whole. It is advantageous, when you consider developing an application,
which should work for large dpi screens and as well as for small dpi screen.
4. Built
in Animation and Video
The Graphics objects can define animation as a property. A button can
be moved from one position to another position using animation effect,
with simple declaration in XAML
For example, an animation effect like 'move the button from top right
corner to bottom left corner within 4 seconds' are easier to define.
With these
advances in the graphics system and by taking advantage of the available
classes in the Windows Presentation Foundation you can build rich Windows
Presentation Framework applications.
