Windows Presentation Foundation

Create a multi threaded web browsing application.

Posted on by coder 
   
  

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MultiBrowse" Height="600" Width="800" Loaded="OnLoaded">
  <StackPanel Name="Stack" Orientation="Vertical">
    <StackPanel Orientation="Horizontal">
      <Button Content="New Window" Click="NewWindowHandler" />
      <TextBox Name="newLocation" Width="500" />
      <Button Content="GO!" Click="Browse" />
    </StackPanel>
    <Frame Name="placeHolder" Width="800" Height="550"></Frame>
  </StackPanel>
</Window>
//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Threading;
using System.Threading;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1() : base()
        {
            InitializeComponent();
        }

        private void OnLoaded(object sender, RoutedEventArgs e)
        {
           placeHolder.Source = new Uri("http://www.kutayzorlu.com/java2s/com");
        }

        private void Browse(object sender, RoutedEventArgs e)
        {
            placeHolder.Source = new Uri(newLocation.Text);
        }
        private void NewWindowHandler(object sender, RoutedEventArgs e)
        {       
            Thread newWindowThread = new Thread(new ThreadStart(ThreadStartingPoint));
            newWindowThread.SetApartmentState(ApartmentState.STA);
            newWindowThread.IsBackground = true;
            newWindowThread.Start();
        }
        private void ThreadStartingPoint()
        {
            Window1 tempWindow = new Window1();
            tempWindow.Show();       
            System.Windows.Threading.Dispatcher.Run();
        }
    }
}

Keep the UI from becoming non-responsive in single threaded application which performs a long operation.

Posted on by coder 


   
  

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Prime Numbers" Width="260" Height="75">
  <StackPanel Orientation="Horizontal" VerticalAlignment="Center" >
    <Button Content="Start" Click="StartOrStop" Name="startStopButton" Margin="5,0,5,0"/>
    <TextBlock Margin="10,5,0,0">Number:</TextBlock>
    <TextBlock Name="numberTextBlock" Margin="4,5,0,0">3</TextBlock>
  </StackPanel>
</Window>
//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Threading;
using System.Threading;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public delegate void NextPrimeDelegate();
        private long num = 1;   

        private bool continueCalculating = false;

        public Window1() : base()
        {
            InitializeComponent();
        }
        public void StartOrStop(object sender, EventArgs e)
        {
            if (continueCalculating)
            {
                continueCalculating = false;
                startStopButton.Content = "Resume";
            }
            else
            {
                continueCalculating = true;
                startStopButton.Content = "Stop";
                startStopButton.Dispatcher.BeginInvoke(DispatcherPriority.Normal,new NextPrimeDelegate(CheckNextNumber));
            }
        }
        public void CheckNextNumber()
        {
            numberTextBlock.Text = num.ToString();
            num += 2;
            if (continueCalculating)
            {
                startStopButton.Dispatcher.BeginInvoke(
                    System.Windows.Threading.DispatcherPriority.SystemIdle, 
                    new NextPrimeDelegate(this.CheckNextNumber));
            }
        }
    }
}

BlockThread.xaml

Posted on by coder 


   
  
<Window x:Class="WPFThreading.BlockThread"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="UI Thread Blocker" Height="275" Width="225"
  >
  <Window.Resources>
    <Style TargetType="{x:Type Button}">
      <Setter Property="Height" Value="20" />
      <Setter Property="Background" Value="Beige"/>
      <Setter Property="Margin" Value="2" />
    </Style>
    <Style TargetType="{x:Type Label}">
      <Setter Property="FontWeight" Value="Bold" />
      <Setter Property="Margin" Value="2" />
    </Style>
    <Style TargetType="{x:Type TextBox}">
      <Setter Property="Margin" Value="2" />
    </Style>
  </Window.Resources>
  <Border Width="200" Height="225" BorderBrush="Black" 
    BorderThickness="1" Margin="4">
    <StackPanel>

      <Label>Simulate Long-Running Process</Label>
      <Button Name="button1" Click="button1_click">Go to sleep</Button>

      <Label>Will I respond?</Label>
      <Button Name="button2" Click="button2_click">Try Me</Button>

      <Label>Output Messages</Label>
      <TextBox Name="textbox1"/>

      <Label/>

      <StackPanel Orientation="Horizontal">
        <Label>UI thread:</Label>
        <Label Name="UIThreadLabel"></Label>
      </StackPanel>

      <StackPanel Orientation="Horizontal">
        <Label>BG thread:</Label>
        <Label Name="BackgroundThreadLabel"></Label>
      </StackPanel>

    </StackPanel>
  </Border>
</Window>

//File:Window.xaml.cs

using System.Windows;

namespace WPFThreading
{

  public partial class BlockThread : System.Windows.Window
  {

    public BlockThread()
    {
      InitializeComponent();

      this.UIThreadLabel.Content = this.Dispatcher.Thread.ManagedThreadId;
      this.BackgroundThreadLabel.Content = "N/A";
    }
    private void button1_click(object sender, RoutedEventArgs e)
    {
      System.Threading.Thread.Sleep(5000);
      this.textbox1.Text = "Done Sleeping...";
    }

    private void button2_click(object sender, RoutedEventArgs e)
    {
      this.textbox1.Text = "Hello WPF";
    }

  }
}

ThreadPool.QueueUserWorkItem

Posted on by coder 


   
  

<Window x:Class="DispatcherExamples.MyWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Use BeginInvoke" Height="300" Width="300"
    >
    <Grid>
      <StackPanel>
        <Button x:Name="useBeginInvokeButton" Content="Use BeginInvoke" />
      </StackPanel>
    </Grid>
</Window>

//File:Window.xaml.cs


using System;
using System.Collections.Generic;
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.Shapes;
using System.Windows.Threading;
using System.Threading;

namespace DispatcherExamples
{
    public partial class MyWindow : System.Windows.Window
    {

        public MyWindow()
        {
            InitializeComponent();

            useBeginInvokeButton.Click += new RoutedEventHandler(useBeginInvokeButton_Click);
        }

        void useBeginInvokeButton_Click(object sender, RoutedEventArgs e)
        {
            ThreadPool.QueueUserWorkItem(delegate
            {
                MyDelegateType methodForUiThread = delegate
                {
                    this.Background = new SolidColorBrush(Color.FromRgb(3,2, 1));
                };
                this.Dispatcher.BeginInvoke(DispatcherPriority.Normal, methodForUiThread);
            });
        }


        public delegate void MyDelegateType();

    }
}

Execute a Method Asynchronously Using the Dispatcher Queue

Posted on by coder 


   
  
<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" Width="220" Height="104" >
    <StackPanel Orientation="Vertical">
        <Button Click="StartStop_Click" Name="btnStartStop">Start</Button>
        <StackPanel Orientation="Horizontal">
            <TextBlock>Biggest Prime Found:</TextBlock>
            <TextBlock Name="txtNumber"/>
        </StackPanel>
    </StackPanel>
</Window>

//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Threading;


namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        private bool continueCalculating = false;

        public Window1() : base()
        {
            InitializeComponent();
        }

        private void StartStop_Click(object sender, RoutedEventArgs e)
        {
            if(continueCalculating)
            {
                continueCalculating = false;
                btnStartStop.Content = "Start";
            }
            else
            {
                continueCalculating = true;
                btnStartStop.Content = "Stop";
                this.Dispatcher.BeginInvoke(DispatcherPriority.Normal,new Action<int>(UpdateNumber), 3);
            }
        }

        public void UpdateNumber(int current)
        {
            txtNumber.Text = current.ToString();
            if(continueCalculating)
            {
                this.Dispatcher.BeginInvoke(DispatcherPriority.SystemIdle,new Action<int>(UpdateNumber), current + 2);
            }
        }
    }

}

Ensure That You Are Running on the UI Thread

Posted on by coder 


   
  

<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>
        <Button Click="ButtonTrue_Click">UI Thread</Button>
        <Button Click="ButtonFalse_Click">Non-UI Thread</Button>
    </StackPanel>
</Window>
//File:Window.xaml.cs
using System.Windows;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void ButtonTrue_Click(object sender, RoutedEventArgs e)
        {
            this.Dispatcher.VerifyAccess();
        }

        private void ButtonFalse_Click(object sender, RoutedEventArgs e)
        {
            VerifyAccessDelegate del = new VerifyAccessDelegate(VerifyAccess);
            del.BeginInvoke(null, null);
        }

        private delegate void VerifyAccessDelegate();

        private void VerifyAccess()
        {
            this.Dispatcher.VerifyAccess();
        }
    }
}

Check Whether You Are Running on the UI Thread

Posted on by coder 


   
  

<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="120" Width="364">
    <StackPanel>
        <Button Click="ButtonTrue_Click">UI Thread</Button>
        <Button Click="ButtonFalse_Click">Non-UI Thread</Button>
        <TextBlock x:Name="txtResult"/>
    </StackPanel>
</Window>
//File:Window.xaml.cs
using System.Windows;
using System.Windows.Threading;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        private delegate void CheckAccessDelegate();
        private delegate void SetResultTextDelegate(string result);
        public Window1()
        {
            InitializeComponent();
        }

        private void ButtonTrue_Click(object sender, RoutedEventArgs e)
        {
            CheckAccess();
        }

        private void ButtonFalse_Click(object sender, RoutedEventArgs e)
        {
            CheckAccessDelegate del = new CheckAccessDelegate(CheckAccess);
            del.BeginInvoke(null, null);
        }

        private void CheckAccess()
        {
            if(txtResult.Dispatcher.CheckAccess())
            {
                txtResult.Text = "True";
            }else{
                txtResult.Dispatcher.BeginInvoke(DispatcherPriority.Normal,new SetResultTextDelegate(SetResultText),"False");
            }
        }

        private void SetResultText(string result)
        {
            txtResult.Text = result;
        }
    }
}