WPF Interview Questions and answers Part 1

1.) What is WPF ?                                                                                                                             
Windows Presentation Foundation (WPF) is nothing but it is the wrapper component on the top of Direct X  Architecture. WPF is a two -dimension (2-D) and three-Dimension (3-D) graphics engine.

• A graphical sub system feature directly related to XAML.
• It is a consistent programming model providing  clear separation between UI and Business logic.
• WPF Application can be deployed on desktop or hosted in web browser.
• The coverage of documents,media and applications.
• WPF is a two dimensional (2-d) and three dimensional (3-d) graphic engine.  

2.) What are the characteristics and capabilities of  WPF ?                                            
There are some features and characteristics of wpf which are given below:-

WPF contains many common user interface components including button,text box ,sliders ,labels and edit boxes etc.

WPF supports 2-d and 3-d animations.

WPF  supports Documents and media into a single environment.

WPF  contains hyperlinks for navigating between documents and tables.

WPF  provides various types of grids and panels to assist in layout.

WPF  supports tier 0 tier 1 and tier 2 Architecture  models.

3.) What is the goal of WPF ?                                                                                                      
There are some goals of WPF:-

• Unified approach to UI,Document and Media :-It Means Integration as a part of development and experience.
• Integrated Vector -based composition engine:-Its goal is Utilize the power of the pc throughout graphics stacks .
• Declarative programming :- In This designer and Developers can easily involve in application development.
• Ease of Deployment :- It allow the administrator to deploy and manage the  application securely.

4.) What is Hardware Acceleration  ?                                                                                      
It is a process by which you can use hardware functionality to perform some functionality   rather than writing the software logic.
5.) What were those technologies which Microsoft launched before WPF   ?        

• User 32 API
• GDI (Graphical device Interface)
• GDI+
• Direct X 

6.) What are three major technologies launched by Microsoft after Direct x  engine ? 

1. Windows Communication Foundation (wcf):- All the protocols communications comes under this section. 
2. Windows Work Flow(WWF):-It helps the developers to make the work flow of the application.
3. Windows Presentation Foundation (WPF):- It is used on the top of Direct X Model.

7.) What do you mean by USER 32 and its problems  ?                                                     
User 32 :- It provides the windows look and feel for text Boxes ,Buttons and other UI elements.User 32 API Provides the drawing capabilities to the users.32 ou can seen this component in window user 32 sub system.The main purpose of user 32 is to give look and feel  in UI element in windows.You can find user 32.dll file in your window.
Problems in User 32:-
If we want to draw line ,rectangle and circle then we can't draw it in User 32 API. To overcome this problem Microsoft launch Next Technology GDI (Graphical user Interface).

8.) What is GDI and its problems  ?                                                                                          
Graphical User Interface (GDI):-There are two main purpose to introduced this technology.

• To improve Drawing capability
• To use high level of abstraction of hardware so that programmer/Developers  can concentrate only  on programming logic not on design part and complexity of hardware is taken care by GDI.

Microsoft Introduced GDI (Graphical Device Interface) to provide drawing capabilities.It is not only provide drawing capabilities but also provide a high level of abstraction on the hard ware display.It encapsulate the all complexity of hardware in  GDI API.

Problem in GDI :-

• GDI API did not support file JPEG ,PNG and anti-aliasing features etc.
• The main issue of GDI was it did not use hardware acceleration.
• It did not support animation and 3-D Features.
• It is never used in game programming.

9.) Why did Microsoft launched GDI+ After GDI  technology ?                                    
To overcome the some problems  of GDI Microsoft launched a new technology ,called GDI+.

10.) What are the features and problems of GDI+ Technology ?                                  
GDI+ is a extended version of GDI.

• It supported the JPG and  PNG  files .
• It supported anti-aliasing features also. 
• It supported Gradient and shading features.

Note:-Hardware acceleration is a process in which we use hardware to perform some functionalities like rectangle/circle drawing etc.rather than performing these functionalities by software which is running in CPU Memory. 

Problem in GDI and GDI+:-

• it did not support hardware acceleration.
• It didn't support animation and 3-D Features.
• It is never used in game programming.

11.) Why did Microsoft launched Direct X After GDI+  technology ?                          
To overcome the problems of GDI and GDI + Microsoft launched a new Technology, called Direct X .