Some Important WPF Classes and Namespaces

Before working with WPF you need to know some common classes and interfaces and their uses. So in this chapter you will get a clear understanding of different classes and interfaces and there uses.  Before knowing the classes and namespaces you need to know, what are the base assemblies that provide different classes ad interfaces for a WPF application. WPF has three base assemblies. These are as below,

1. WindowsBase.dll: This assembly defines the core types that constitute the infrastructure WPF API.
2. PresentationCore.dll: As the name specifies this assembly specifies different types for WPF GUI layer.
3. PresentationFoundation.dll: It defines the WPF control types, animation, multimedia and data binding support. It also specifies some other functionality.
4. The above three namespaces are managed namespaces. Besides these three namespaces WPF also uses an unmanaged library, i.e. milcore.dll. This library is responsible to work with DirectX layer. It acts as a bridge between the managed WPF assemblies and the DirectX layer.

Some WPF Classes:

All these three assemblies provides a number of new namespaces and hundreds of new .NET types(classes, interfaces, structures, enumerations and delegates) to work with WPF. The following class diagram and the class’s functionality.

• DispatcherObject: It is an abstract base class for classes that are bound to one thread. Classes that are derived from DispatcherObject have an associated Dispatcher object that can be used to switch the threads.
• Application: In every WPF application, one instance of Application class is created. This class implements a singleton pattern for access to the window of application, resources and properties. See the below image.
   

• DependencyObject:  It is the base class for all the classes that supports Dependency property.
• Visual: It is the base class for all the visual elements of WPF. This class includes features for transformation.
• UIElement:  It is the abstract base class for all WPF elements that need basic presentation feature. This class provides evens such as mouse move, drag and drop, click, etc.
• FrameworkElement:  It is derived from base class UIElements and implements the default behaviour of the methods defined by the base class.
• Shape: Shape is the base class for all the shape elements such as, line, rectangle, ellipse, polygon.
• Control: It is derived from FrameworkElement and is the base class for all the user-interactive elements.
• Panel:  As the name suggest it is the abstract base class for all the panels and is derived from FrameworkElement. Panel class has a Children property for all the UI-Element that is inside a panel and defines methods for arranging the child controls. Panel defines different classes to define the behaviour of child controls such as, WrapPanel, StackPanel, Grid and Canvas.
• ContentControl: - It is the base class for all the controls that have a single content such as, Buttons, Labels, CheckBox, RadioButton, etc.

You can also find the class hierarchy of your application using Object Browser in VS 2008. To view Object Browser go to view menu and select Object Browser. Object Browser also contains all the namespaces and its classes. See the below image for WPF class hierarchy. It is the class hierarchy of a simple WPF application that we have created earlier. Using Object Browser you can find all the methods, properties and events of a particular class by selecting that class.
 

Some WPF Namespaces:

• System. Windows:- It is the core namespace of WPF. You will find all the base classes such as, Application, DependencyObject , DependencyProperty and FrameworkElement here.
• System. Windows. Controls:- This namespaces contains all the controls of WPF. You will also find classes to work with complex controls such as PopUp, ScrollBar, StatusBar, TabPanel, etc. as well as all the basic controls.
• System. Windows. Data:- This namespace is used by WPF for Data Binding.
• System. Windows. Input:- This namespace provides several classes for command handling, keyboard input, etc.
• System. Windows. Markup:- This namespace helper classes for XAML markup code.
• System. Windows. Media:- This namespace is responsible to work with images, audio, and multimedia.
• System. Windows. Shapes:- This namespace provides core classes for UI such as Line, Rectangle, Ellipse, etc.
• System. Windows. Threading:- This namespace provides classes to work with multiple threads.
• System. Windows. Navigation:- This namespace provides classes for navigation between WPF pages particularly when working with Web Applications.

Applications of WPF

WPF has comprehensive features for creating user experiences with rich content. To package this content and deliver it to users as "applications," WPF provides types and services that are collectively known as the application model. The application model supports the development of both standalone and browser-hosted applications.

Standalone Applications
    For standalone applications, you can use the Window class to create windows and dialog boxes that are accessed from menu bars and tool bars.

Additionally, you can use the following WPF dialog boxes: MessageBox, OpenFileDialog, SaveFileDialog, and PrintDialog.

Like in below image-

Browser-Hosted Applications
For browser-hosted applications, known as XAML browser applications (XBAPs), you can create pages (Page) and page functions (PageFunction<T>) that you can navigate between using hyperlinks (Hyperlink classes).
For Browser-Hosted Application we will discuss later.

Now we are starting with Standalone Application.

Controls in Windows WPF-
                The built-in WPF controls are listed here.

   Buttons: Button and RepeatButton.
   Dialog Boxes: OpenFileDialog, PrintDialog, and SaveFileDialog.
   Digital Ink: InkCanvas and InkPresenter.
   Documents: DocumentViewer, FlowDocumentPageViewer, FlowDocumentReader, FlowDocumentScrollViewer, and StickyNoteControl.
   Input: TextBox, RichTextBox, and PasswordBox.
   Layout: Border, BulletDecorator, Canvas, DockPanel, Expander, Grid, GridView, GridSplitter, GroupBox, Panel, ResizeGrip, Separator, ScrollBar, ScrollViewer, StackPanel, Thumb, Viewbox, VirtualizingStackPanel, Window, and WrapPanel.
   Media: Image, MediaElement, and SoundPlayerAction.
   Menus: ContextMenu, Menu, and ToolBar.
   Navigation: Frame, Hyperlink, Page, NavigationWindow, and TabControl.
   Selection: CheckBox, ComboBox, ListBox, TreeView, RadioButton, and Slider.
   User Information: AccessText, Label, Popup, ProgressBar, StatusBar, TextBlock, and ToolTip.

Programming With WPF

The fundamental of  WPF programming is very  familiar to the Windows and web Application. You can  instantiate classes, set properties, call methods, and handle events, all using your favorite .NET Framework programming language, such as C# or Visual Basic. WPF exists as a subset of .NET Framework types that are for the most part located in the System.Windows namespace.
WPF includes additional programming constructs that enhance properties and events: Dependency Properties and Routed Events

Markup and Code-Behind

WPF offers additional programming enhancements for Windows client application development. One obvious enhancement is the ability to develop an application using both markup and code-behind, an experience that ASP.NET developers should be familiar with. Development and maintenance costs are reduced because appearance-specific markup is not tightly coupled with behavior-specific code.

Development is more efficient because designers can implement an application's appearance simultaneously with developers who are implementing the application's behavior.
Multiple design tools can be used to implement and share XAML markup, to target the requirements of the application development contributors.
Globalization and localization for WPF applications is greatly simplified

Markup

XAML is an XML-based markup language that is used to implement an application's appearance declaratively. It is typically used to create windows, dialog boxes, pages, and user controls, and to fill them with controls, shapes, and graphics.

Code-Behind

The main behavior of an application is to implement the functionality that responds to user interactions, including handling events (for example, clicking a menu, tool bar, or button) and calling business logic and data access logic in response. In WPF, this behavior is generally implemented in code that is associated with markup. This type of code is known as code-behind.

To understand Code behind i have taken example for Button click event to show the message box. For this just double click on Button you will go to the code behind of button and write the code as follows for button click event. 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            // Show message box when button is clicked
          
            MessageBox.Show("Welcome to WPF Programming!");
        }
    }
}

Introduction To WPF

WPF stands for Windows Presentation Foundation (WPF) is a next-generation presentation system for building Windows client applications with visually stunning user experiences. With WPF, you can create a wide range of both standalone and browser-hosted applications.

The core of WPF is a resolution-independent and vector-based rendering engine that is built to take advantage of modern graphics hardware. WPF extends the core with a comprehensive set of application-development features that include Extensible Application Markup Language (XAML), controls, data binding, layout, 2-D and 3-D graphics, animation, styles, templates, documents, media, text, and typography. WPF is included in the Microsoft .NET Framework, so you can build applications that incorporate other elements of the .NET Framework class library.

Architecture of WPF

Go to File menu choose new project and then WPF Application-as shown in below picture.

Then you will get space for working like in below picture.

Extensible Application Markup Language (XAML)

XAML is an XML based language that is used as a foundation for the WPF. It allows forms to be created using a syntax very similar to ASP.NET and HTML. For example, a button in html:

<input type="button" value="Click Me" id="myButton" />

and In WPF

<Button Name="myButton">Click Me<Button>