Author: coder

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();
        }
    }
}

Use a Thumb to resize a Canvas control by responding to the DragDelta event.

Posted on by coder 


   
  

<Canvas xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="Thumb_wcp.Pane1">
  <Canvas Width="100" Height="100" Name="myCanvasStretch">
    <TextBox Name="changes" 
         Width="{Binding ElementName=myCanvasStretch,Path=Width}"  
         Height="{Binding ElementName=myCanvasStretch,Path=Height}" 
         Text="Size: 100, 100"/>
    <Thumb Name="myThumb" Canvas.Left="80" Canvas.Top="80" Background="Blue" 
          Width="20" Height="20" DragDelta="onDragDelta"/>
  </Canvas>
</Canvas>
//File:Window.xaml.cs


using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Documents;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Data;
using System.Windows.Media;

namespace Thumb_wcp
{
    public partial class Pane1 : Canvas
    {
        void onDragDelta(object sender, DragDeltaEventArgs e)
        {
            double yadjust = myCanvasStretch.Height + e.VerticalChange;
            double xadjust = myCanvasStretch.Width + e.HorizontalChange;
            if ((xadjust >= 0) &amp;&amp; (yadjust >= 0))
            {
                myCanvasStretch.Width = xadjust;
                myCanvasStretch.Height = yadjust;
                Canvas.SetLeft(myThumb, Canvas.GetLeft(myThumb) + e.HorizontalChange);
                Canvas.SetTop(myThumb, Canvas.GetTop(myThumb) + e.VerticalChange);
                Console.WriteLine(myCanvasStretch.Width);
                Console.WriteLine(myCanvasStretch.Height);
            }
        }

    }
}

Thumb DragStarted and DragCompleted event handler

Posted on by coder 


   
  
<Canvas xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="Thumb_wcp.Pane1">
  <StackPanel>
    <Thumb Name="myThumb" Background="Blue" 
          Width="20" Height="20" 
          DragStarted="onDragStarted" DragCompleted="onDragCompleted"/>
  </StackPanel>
</Canvas>

//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Documents;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Data;
using System.Windows.Media;

namespace Thumb_wcp
{
    public partial class Pane1 : Canvas
    {

        void onDragStarted(object sender, DragStartedEventArgs e)
        {
            myThumb.Background = Brushes.Orange;
        }
        void onDragCompleted(object sender, DragCompletedEventArgs e)
        {
            myThumb.Background = Brushes.Blue;
        }
    }
}

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;
        }
    }
}

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();
        }
    }
}

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);
            }
        }
    }

}

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();

    }
}