Introduction of WPF

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.

WPF separates the appearance of an user interface from its behavior. The appearance is generally specified in the Extensible Application Markup Language (XAML), the behavior is implemented in a managed programming language like C# or Visual Basic. The two parts are tied together by databinding, events and commands. The separation of appearance and behavior brings the following benefits:

• Appearance and behaviour are loosely coupled
• Designers and developers can work on separate models.
• Graphical design tools can work on simple XML documents instead of parsing code.

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.

How to create a simple WPF application

Open Visual Studio 2008 and choose "File", "New", "Project..." in the main menu. Choose "WPF Application" as project type.

Choose a folder for your project and give it a name. Then press "OK"

Visual Studio creates the project and automatically adds some files to the solution. A Window1.xaml and an App.xaml. The structure looks quite similar to WinForms, except that the Window1.designer.cs file is no longer code but it's now declared in XAML as Window1.xaml

Open the Window1.xaml file in the WPF designer and drag a Button and a TextBox from the toolbox to the Window

Select the Button and switch to the event view in the properties window (click on the little yellow lightning icon). Doubleclick on the "Click" event to create a method in the codebehind that is called, when the user clicks on the button.

Note: If you do not find a yellow lightning icon, you need to install the Service Pack 1 for VisualStudio on your machine. Alternatively you can doubleclick on the button in the designer to achieve the same result.

Visual Studio automatically creates a method in the code-behind file that gets called when the button is clicked.

 
private void button1_Click(object sender, RoutedEventArgs e)
{
    textBox1.Text = "Hello WPF!";
}
 
 

The textbox has automatically become assigned the name textBox1 by the WPF designer. Set text Text to "Hello WPF!" when the button gets clicked and we are done! Start the application by hit [F5] on your keyboard.

 <!--Amit Kumar jha-->

Download the WPF Toolkit - either source or binaries (the toolkit is entirely open source).

Example:

<Window
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="SDKSample.DataTemplateWindow"
  Title="With a Data Template">


...


<Window.Resources>
  <!-- Data Template (applied to each bound task item in the task collection) -->
  <DataTemplate x:Key="myTaskTemplate">
    <Border Name="border" BorderBrush="DarkSlateBlue" BorderThickness="2" 
      CornerRadius="2" Padding="5" Margin="5">
      <Grid>
        <Grid.RowDefinitions>      
          <RowDefinition/>
          <RowDefinition/>
          <RowDefinition/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
          <ColumnDefinition Width="Auto" />
          <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Row="0" Grid.Column="0" Padding="0,0,5,0" Text="Task Name:"/>
        <TextBlock Grid.Row="0" Grid.Column="1" Text="{Binding Path=TaskName}"/>
        <TextBlock Grid.Row="1" Grid.Column="0" Padding="0,0,5,0" Text="Description:"/>
        <TextBlock Grid.Row="1" Grid.Column="1" Text="{Binding Path=Description}"/>
        <TextBlock Grid.Row="2" Grid.Column="0" Padding="0,0,5,0" Text="Priority:"/>
        <TextBlock Grid.Row="2" Grid.Column="1" Text="{Binding Path=Priority}"/>
      </Grid>
    </Border>  
  </DataTemplate>
</Window.Resources>


...


<!-- UI -->
<DockPanel>
  <!-- Title -->
  <Label DockPanel.Dock="Top" FontSize="18" Margin="5" Content="My Task List:"/>

  <!-- Data template is specified by the ItemTemplate attribute -->
  <ListBox 
    ItemsSource="{Binding}" 
    ItemTemplate="{StaticResource myTaskTemplate}" 
    HorizontalContentAlignment="Stretch" 
    IsSynchronizedWithCurrentItem="True" 
    Margin="5,0,5,5" />

</DockPanel>


...


</Window>

Introduction to XAML

XAML stands for Extensible Application Markup Language. Its a simple language based on XML to create and initialize .NET objects with hierarchical relations. Altough it was originally invented for WPF it can by used to create any kind of object trees.

Today XAML is used to create user interfaces in WPF, Silverlight, declare workflows in WF and for electronic paper in the XPS standard.

All classes in WPF have parameterless constructors and make excessive usage of properties. That is done to make it perfectly fit for XML languages like XAML.

Advantages of XAML

All you can do in XAML can also be done in code. XAML ist just another way to create and initialize objects. You can use WPF without using XAML. It's up to you if you want to declare it in XAML or write it in code. Declare your UI in XAML has some advantages:

XAML code is short and clear to read
Separation of designer code and logic
Graphical design tools like Expression Blend require XAML as source.
The separation of XAML and UI logic allows it to clearly separate the roles of designer and developer.


XAML vs. Code

As an example we build a simple StackPanel with a textblock and a button in XAML and compare it to the same code in C#.

 
<StackPanel>
    <TextBlock Margin="20">Welcome to the World of XAML</TextBlock>
    <Button Margin="10" HorizontalAlignment="Right">OK</Button>
</StackPanel>
 
 


The same expressed in C# will look like this:

 
// Create the StackPanel
StackPanel stackPanel = new StackPanel();
this.Content = stackPanel;
 
// Create the TextBlock
TextBlock textBlock = new TextBlock();
textBlock.Margin = new Thickness(10);
textBlock.Text = "Welcome to the World of XAML";
stackPanel.Children.Add(textBlock);
 
// Create the Button
Button button = new Button();
button.Margin= new Thickness(20);
button.Content = "OK";
stackPanel.Children.Add(button);
 
 


As you can see is the XAML version much shorter and clearer to read. And that's the power of XAMLs expressiveness.

Properties as Elements

Properties are normally written inline as known from XML <Button Content="OK" />. But what if we want to put a more complex object as content like an image that has properties itself or maybe a whole grid panel? To do that we can use the property element syntax. This allows us to extract the property as an own child element.

 
<Button>
  <Button.Content>
     <Image Source="Images/OK.png" Width="50" Height="50" />
  </Button.Content>
</Button>
 
 


Implicit Type conversion

A very powerful construct of WPF are implicit type converters. They do their work silently in the background. When you declare a BorderBrush, the word "Blue" is only a string. The implicit BrushConverter makes aSystem.Windows.Media.Brushes.Blue out of it. The same regards to the border thickness that is beeing converted implicit into a Thickness object. WPF includes a lot of type converters for built-in classes, but you can also write type converters for your own classses.

 
<Border BorderBrush="Blue" BorderThickness="0,10">
</Border>
 
 


Markup Extensions

Markup extensions are dynamic placeholders for attribute values in XAML. They resolve the value of a property at runtime. Markup extensions are surrouded by curly braces (Example: Background="{StaticResource NormalBackgroundBrush}"). WPF has some built-in markup extensions, but you can write your own, by deriving fromMarkupExtension. These are the built-in markup extensions:






Namespace

At the beginning of every XAML file you need to include two namespaces. 
The first is http://schemas.microsoft.com/winfx/2006/xaml/presentation. It is mapped to all wpf controls inSystem.Windows.Controls. 
The second is http://schemas.microsoft.com/winfx/2006/xaml it is mapped to System.Windows.Markup that defines the XAML keywords.
The mapping between an XML namespace and a CLR namespace is done by the XmlnsDefinition attribute at assembly level. You can also directly include a CLR namespace in XAML by using the clr-namespace: prefix.



WPF Calendar Control


Set the displayed date

The calendar displays by default the current date. But you can specify any other date to be displayed by setting theDisplayDate property.

 
<Calendar DisplayDate="01.01.2010" />
 
 


Selection Modes

The calendar control provides multiple modes for selection. You can set the SelectionMode property toSingleDateSingleRange, MultipleRanges or None.

 
<Calendar SelectionMode="MultipleRange" />
 
 


Blackout dates

The calendar control provides a feature to black out dates that are not valid for selection. You can define multiple ranges by setting the BlackoutDates property to one or multiple CalendarDateRange.

 
<Calendar SelectionMode="{Binding SelectedItem, ElementName=selectionmode}" >
    <Calendar.BlackoutDates>
        <CalendarDateRange Start="01/01/2010" End="01/06/2010" />
        <CalendarDateRange Start="05/01/2010" End="05/03/2010" />
    </Calendar.BlackoutDates>
</Calendar>
 
 


Calendar Modes

The calendar supports three modes to display ranges of dates: Year, Month and Decade. You can control the mode by setting the DisplayMode property.

 
<Calendar DisplayMode="Year" />