<Window x:Class="WpfApplication1.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="Window1" Height="100" Width="200">
  <StackPanel>
    <TextBox x:Name="tbxUserText" Text="Enter some text..."/>
    <Button Click="Button_Click" Content="Update DataContext"/>
  </StackPanel>
</Window>

//File:Window.xaml.cs
using System.Windows;
using System;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContextProperty.OverrideMetadata(
                typeof(Window1), 
                new FrameworkPropertyMetadata(
                        100d, 
                        new PropertyChangedCallback(DataContext_PropertyChanged)));

        }

        private static void DataContext_PropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            string msg = string.Format("DataContext changed.{0}{0}Old Value: {1}{0}New Value: {2}",
                              Environment.NewLine,
                              e.OldValue.ToString(), 
                              e.NewValue.ToString());

            MessageBox.Show(msg, "changed");
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            DataContext = tbxUserText.Text;            
        }
    }
}

   
    
     

   
  

<Window x:Class="WpfApplication1.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="Window1" Height="100" Width="200">
  <StackPanel>
    <TextBox x:Name="tbxUserText" Text="Enter some text..."/>
    <Button Click="Button_Click" Content="Update DataContext"/>
  </StackPanel>
</Window>

//File:Window.xaml.cs
using System.Windows;
using System;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            DataContextProperty.OverrideMetadata(
                typeof(Window1), 
                new FrameworkPropertyMetadata(
                        100d, 
                        new PropertyChangedCallback(DataContext_PropertyChanged)));

        }

        private static void DataContext_PropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            string msg = string.Format("DataContext changed.{0}{0}Old Value: {1}{0}New Value: {2}",
                              Environment.NewLine,
                              e.OldValue.ToString(), 
                              e.NewValue.ToString());

            MessageBox.Show(msg, "changed");
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            DataContext = tbxUserText.Text;            
        }
    }
}

   
    
     

   
  
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:s="clr-namespace:System;assembly=mscorlib">
    <Page.Resources>

        <DataTemplate DataType="{x:Type s:Int32}">
            <StackPanel Orientation="Horizontal">
                <TextBlock Text="Integer: " />
                <TextBlock Text="{Binding}" />
            </StackPanel>
        </DataTemplate>

    </Page.Resources>

    <StackPanel>
        <Button>
            <s:Int32>1</s:Int32>
        </Button>

    </StackPanel>
</Page>

   
    
     

   
  
<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="100" Width="300">
    <StackPanel>
        <ComboBox Name="comboBox" IsEditable="True" Margin="5" SelectionChanged="ComboBox_SelectionChanged">
            <ComboBoxItem Content="ComboBox Item 1" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 2" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 3" Selected="ComboBoxItem_Selected" IsSelected="True"/>
            <ComboBoxItem Content="ComboBox Item 4" Selected="ComboBoxItem_Selected" />
            <ComboBoxItem Content="ComboBox Item 5" Selected="ComboBoxItem_Selected" />
        </ComboBox>
        <Button Content="Get Selected" Margin="5" Width="100" Click="Button_Click" />
    </StackPanel>
</Window>

//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            ComboBoxItem item = comboBox.SelectedItem as ComboBoxItem;

            if (item != null)
            {
                MessageBox.Show("Current item: " + item.Content, Title);
            }
            else if (!String.IsNullOrEmpty(comboBox.Text))
            {
                MessageBox.Show("Text entered: " + comboBox.Text, Title);
            }
        }

        private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {

            if (!IsInitialized) return;

            ComboBoxItem item = comboBox.SelectedItem as ComboBoxItem;

            if (item != null)
            {
                MessageBox.Show("Selected item: " + item.Content, Title);
            }
        }

        private void ComboBoxItem_Selected(object sender,RoutedEventArgs e)
        {
            if (!IsInitialized) return;

            ComboBoxItem item = e.OriginalSource as ComboBoxItem;

            if (item != null)
            {
                MessageBox.Show(item.Content + " was selected.", Title);
            }
        }
    }
}

   
    
     

   
  

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF WpfApplication1" Height="180" Width="260">
    <StackPanel>
        <TextBlock Text="Last Name" VerticalAlignment="Center"/>
        <TextBox Text="{Binding Path=LastName, Mode=TwoWay}"/>
        
        <TextBlock Text="Age" VerticalAlignment="Center"/>
        <TextBox Text="{Binding Path=Age, Mode=TwoWay}"/>
        
        <TextBlock Text="Occupation" VerticalAlignment="Center"/>
        <ComboBox x:Name="cboOccupation" IsEditable="False" HorizontalAlignment="Left"
            Text="{Binding Path=Occupation, Mode=TwoWay}"
            Margin="4" Width="140">
             <ComboBoxItem>Student</ComboBoxItem>
             <ComboBoxItem>Skilled</ComboBoxItem>
             <ComboBoxItem>Professional</ComboBoxItem>
        </ComboBox>
                  
        <TextBlock Margin="4" Text="Description" FontWeight="Bold" FontStyle="Italic" VerticalAlignment="Center"/>
        <TextBlock Margin="4" Text="{Binding Path=Description, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center"/>
        
    </StackPanel>
</Window>
//File:Window.xaml.cs
using System.Windows;
using System.ComponentModel;
namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            
            this.DataContext = new Employee(){
                        LastName = "B",
                        Age = 26,
                        Occupation = "Professional"
            };
        }
    }

    public class Employee : INotifyPropertyChanged
    {
        private string lastName;
        private int age;
        private string occupation;

        public string LastName
        {
            get
            {
                return lastName;
            }
            set
            {
                if(this.lastName != value)
                {
                    this.lastName = value;
                    OnPropertyChanged("LastName");
                    OnPropertyChanged("Description");
                }
            }
        }

        public int Age
        {
            get
            {
                return age;
            }
            set
            {
                if(this.age != value)
                {
                    this.age = value;
                    OnPropertyChanged("Age");
                    OnPropertyChanged("Description");
                }
            }
        }
        
        public string Occupation
        {
            get { return occupation; }
            set
            {
                if (this.occupation != value)
                {
                    this.occupation = value;
                    OnPropertyChanged("Occupation");
                    OnPropertyChanged("Description");
                }
            }
        }

        public string Description
        {
            get
            {
                return string.Format("{0} {1}, ({2})", 
                                      lastName, age, occupation);
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyName)
        {
            if(this.PropertyChanged != null)
            {

                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }

    }
}

   
    
     

   
       


<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <StackPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                Orientation="Horizontal" Height="25">
      <Button Command="Cut" CommandTarget="{Binding ElementName=textBox}"
        Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <Button Command="Copy" CommandTarget="{Binding ElementName=textBox}"
        Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <Button Command="Paste" CommandTarget="{Binding ElementName=textBox}"
        Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <Button Command="Undo" CommandTarget="{Binding ElementName=textBox}"
        Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <Button Command="Redo" CommandTarget="{Binding ElementName=textBox}"
        Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <TextBox x:Name="textBox" Width="200"/>
    </StackPanel>
    

</Page>

   
    
    
    
    
    
    
     

   
  

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="AboutDialog"
        Title="About WPF Unleashed" SizeToContent="WidthAndHeight"
        Background="OrangeRed">
  <Window.CommandBindings>
    <CommandBinding Command="Help" CanExecute="HelpCanExecute" Executed="HelpExecuted"/>
  </Window.CommandBindings>
  <StackPanel>
    <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
      <Button MinWidth="75" Margin="10" Command="Help" Content="{Binding RelativeSource={RelativeSource Self}, Path=Command.Text}"/>
      <Button MinWidth="75" Margin="10">OK</Button>
    </StackPanel>
    <StatusBar>asdf</StatusBar>
  </StackPanel>
</Window>

//File:Window.xaml.cs

using System.Windows;
using System.Windows.Input;

public partial class AboutDialog : Window
{
    public AboutDialog()
    {
        InitializeComponent();
    }

    void HelpCanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = true;
    }
    
    void HelpExecuted(object sender, ExecutedRoutedEventArgs e)
    {
        System.Diagnostics.Process.Start("http://www.kutayzorlu.com/java2s/com");
    }
}