Progress Bar in WPF With Anonymous Delegates

Here I created a WPF Progress Bar that will demonstrate many terms, like Threading, Synchronization, Invoke() and begineInvoke() and simplicity!

Progress Bar in WPF

Step 1: Create WPF Project.

Step 2: Drag two Buttons and a Progress Bar to the WPF Window.

The following are some point to be noted:

To update progress bar you need to start new thread, Other than the main thread of GUI; that can update progress bar!
WPF, or Control in the case of Windows Forms have thread affinity, which means that only the thread that instantiates them.
But can subsequently access their members. Violating this causes either unpredictable behavior, or an exception to be thrown. (for e.g if you want to call a member on object X created on another thread Y, you must marshal the request to thread Y).
Solution : In WPF you can Use "Dispatcher" Object of "Control" (here Progress bar) to start a new thread.
Same solution can be done with BackgroundWorker and Task Objects.

XAML CODE

<Window x:Class="ThreadsProgressBar.MainWindow"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Title="MainWindow" Height="350" Width="525" Closing="Window_Closing">

<Grid>

</Grid>

</Window>

CODE BEHIND

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Windows;

using System.Windows.Controls;

using System.Threading;

using System.Windows.Threading;

namespace ThreadsProgressBar

{

/// <summary>

/// Developer Name : void

/// Email For Comments : [email protected]

/// Message : Welcome !

/// Interaction logic for MainWindow.xaml

/// </summary>

public partial class MainWindow : Window

{

// Start New Thread here -- Globally --

Thread t = null;

public MainWindow()

{

InitializeComponent();

// You can set this Max limit in XAML also !

progressBar1.Maximum = 100;

}

private void Work()

{

// Do You Expensive Work Here!

for (int i = 0; i <= 100; i++)

{

//This Sleep is Just For Some timepass

Thread.Sleep(100);

UpdateProgressBar(i);

}

MessageBox.Show("Finish !");

}

private void UpdateProgressBar(int i)

{

// Action is delegate (means a function pointer) which is Pointing towards "SetProgress" method

Action action = () => { SetProgress(i);};

// Here Dispacthers Invoke (is a Syncronus)/ BegineInvoke (Is Asyncornus) in Called

progressBar1.Dispatcher.BeginInvoke(action);

}

private void SetProgress(int i)

{

progressBar1.Value = i;

}

// Start Thread Button Code

private void button1_Click(object sender, RoutedEventArgs e)

{

// Thread is started here (We can say this is 2nd thread after main Thread !)

t = new Thread(Work);

t.Start();

}

private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)

{

if (t.IsAlive)

t.Abort();

}

// Abort Thread Button Code

private void button2_Click(object sender, RoutedEventArgs e)

{

// Aborti ng Thread here !

if (t.IsAlive)

{

t.Abort();

progressBar1.Value = 0;

}

WINODW

/Progress bar in WPF with Anonymous delegates

Thanks! I hope this will help someone!