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progress bar in background worker get argument which being updated in the main thread c# wpf

I have the main thread which is wizard in WPF.
after user finished set the properties of the wizard, it processing data.
It takes a few seconds and I would like to raise a progress bar which report on the progress.
Hence, I set always on the main thread variable call currentStep.
I have totally thresholdStep steps which equals to 12.
So I want that the progress bar will work as a thread but it will also will be connected to the main thread by using currentStep variable.
So, I used by background worker like this:
public partial class MessageWithProgressBar : Window
{
private BackgroundWorker backgroundWorker = new BackgroundWorker();
public MessageWithProgressBar()
{
InitializeComponent();
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.ProgressChanged += ProgressChanged;
backgroundWorker.DoWork += DoWork;
backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;
}
private void DoWork(object sender, DoWorkEventArgs e)
{
Thread.Sleep(100);
int i = (int)e.Argument;
backgroundWorker.ReportProgress((int)Math.Floor((decimal)(8*i)));
if (i > GeneralProperties.General.thresholdStep)
backgroundWorker.ReportProgress(100);
}
private void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progress.Value = e.ProgressPercentage;
}
private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
WindowMsg msg = new WindowMsg();
msg.Show();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
if (backgroundWorker.IsBusy == false)
backgroundWorker.RunWorkerAsync(GeneralProperties.General.currentStep);
}
}
In addition, I called the background worker from the main thread as below:
MessageWithProgressBar progress = new MessageWithProgressBar();
progress.Show();
What acutally happens is that DoWork called only once with currentStep = 1 and it don't updates in relation to the main thread which also updated currentStep dependents on it's progress.
Any ideas how to solve it?
Thanks!

Change your DoWork method like below:
private void DoWork(object sender, DoWorkEventArgs e)
{
Thread.Sleep(100);
int i = (int)e.Argument;
do
{
i = GeneralProperties.General.currentStep;
backgroundWorker.ReportProgress((int)Math.Floor((decimal)(8 * i)));
if (i > GeneralProperties.General.thresholdStep)
backgroundWorker.ReportProgress(100);
}
while (i < GeneralProperties.General.thresholdStep);
}
Just make sure your are not getting thread synchronization problem with GeneralProperties.General object, if you are then use lock when accessing the object.
UPDATE:
For update problem:
private void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
System.Windows.Application.Current.Dispatcher.Invoke(new Action(() =>
{
progress.Value = e.ProgressPercentage;
}), null);
}

How do I keep a BackgroundWorker from blocking the UI thread?

In my XML editor I want to be able to open multiple files at once using an index file. Obviously, depending on the amount of files, this can take a bit of time and I want to use a progress bar to notify the user that the programm is still loading and doing something.
From what I have researched the way to keep the UI progress bar updated is using a BackgroundWorker.
public MainWindow()
{
InitializeComponent();
tabList = new ObservableCollection<FileTab>();
tabControl.ItemsSource = tabList;
backgroundWorker = new BackgroundWorker();
backgroundWorker.DoWork += backgroundWorker_DoWork;
backgroundWorker.ProgressChanged += backgroundWorker_ProgressChanged;
backgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;
backgroundWorker.WorkerReportsProgress = true;
}
(...)
private void OpenProjectButtonClick(object sender, RoutedEventArgs e)
{
openingProgressBar.Value = 0;
openingProgressBar.Visibility = System.Windows.Visibility.Visible;
backgroundWorker.RunWorkerAsync();
}
void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
int i = 0;
foreach (IndexFile file in indexManager.fileList)
{
this.Dispatcher.Invoke((Action)(() =>
{
tabList.Add(new FileTab(file.filePath));
}));
i++;
Console.WriteLine("-(DoWork)->" + i);
double percentage = (Convert.ToDouble(i) / Convert.ToDouble(indexManager.fileList.Count)) * 100;
Console.WriteLine("-(DoWork.percentage)-> "+ percentage);
backgroundWorker.ReportProgress((int)percentage);
}
}
void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
openingProgressBar.Value = e.ProgressPercentage;
Console.WriteLine("-(ProgressChanged)->" + openingProgressBar.Value);
}
void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
openingProgressBar.Visibility = System.Windows.Visibility.Collapsed;
backgroundWorker.Dispose();
Console.WriteLine("-(RunWorkerComplete)-> Done");
}
Since I'm accessing the tablist in the DoWork-Method I wrap that call in the Dispathcer.Invoke. In this form the code kind of does what I want. It makes the collapsed progressBar visible and updates it every once in a while. Sadly it doesn't update the percentage after every file loaded. From what I can see in the console, the ProgressChanged execution lags behind the DoWork. From my understanding it is called in every iteration of the loop though. And even if it fires the UI doesn't always respond to that.
So my question is: Am I still blocking the UI thread somehow and how could I fix it?

The Problem is that
you are do a coupling between UI and BackgroundWorker
The Solution
return on ReportProgress your FileTab object
void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
int i = 0;
foreach (IndexFile file in indexManager.fileList)
{
i++;
Console.WriteLine("-(DoWork)->" + i);
double percentage = (Convert.ToDouble(i) / Convert.ToDouble(indexManager.fileList.Count)) * 100;
Console.WriteLine("-(DoWork.percentage)-> "+ percentage);
backgroundWorker.ReportProgress((int)percentage,new FileTab(file.filePath));
}
}
then add your FileTab object in your backgroundWorker_ProgressChanged to the tabList

Try to move the reporting progress operation into the dispatcher's operations:
foreach (IndexFile file in indexManager.fileList)
{
this.Dispatcher.Invoke((Action)(() =>
{
tabList.Add(new FileTab(file.filePath));
Console.WriteLine("-(DoWork)->" + i);
double percentage = (Convert.ToDouble(i) / Convert.ToDouble(indexManager.fileList.Count)) * 100;
Console.WriteLine("-(DoWork.percentage)-> "+ percentage);
backgroundWorker.ReportProgress((int)percentage);
}));
i++;
}
It's possible that dispatcher runs in another thread...

How to make a progressbar run in a different thread in C#

I want to create a basic multi-thread application using a progress bar. Meaning that this progress bar will run on a different thread while the main thread is busy in the large process it is doing. I've seen a lot of tutorials about it. But the thing that they are multi-threading is the one that doing the large process. The progress bar in the other form is just showing a simple progress bar that runs and complete using a timer.
This is the code I have now.
For the thread:
public void thread()
{
Form6 for6 = new Form6();
for6.Show();
}
TH1 = new Thread(thread);
TH1.Start();
For the progress bar (Code inside form 6)
private void timer1_Tick(object sender, EventArgs e)
{
progressBar1.Increment(+1);
if (progressBar1.Value == 99)
{
this.Close();
}
}
private void Form6_Load(object sender, EventArgs e)
{
timer1.Start();
}
My problem is the thread in here doesn't run the Form6. Is there any way for me to do this?

Instead of using main thread for large processing you can use the Background worker for all the processing.
Here's a simple example to do it.
public partial class Form1 : Form
{
BackgroundWorker bgw = new BackgroundWorker();
public Form1()
{
InitializeComponent();
label1.Text = "";
label2.Text = "";
}
private void button1_Click_1(object sender, EventArgs e)
{
bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
bgw.WorkerReportsProgress = true;
bgw.RunWorkerAsync();
}
void bgw_DoWork(object sender, DoWorkEventArgs e)
{
int total = 57; //some number (this is your variable to change)!!
for (int i = 0; i <= total; i++) //some number (total)
{
System.Threading.Thread.Sleep(100);
int percents = (i * 100) / total;
bgw.ReportProgress(percents, i);
//2 arguments:
//1. procenteges (from 0 t0 100) - i do a calcumation
//2. some current value!
}
}
void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
label1.Text = String.Format("Progress: {0} %", e.ProgressPercentage);
label2.Text = String.Format("Total items transfered: {0}", e.UserState);
}
void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
//do the code when bgv completes its work
}
}

Instead of the ProgressBar, you should really move your long-running, non-UI code into a separate thread. The standard and easier way of doing this in WinForms is to use BackgroundWorker component, which can raise ProgressChanged event where you can update your UI. Important to note that ProgressChanged event is raised on the UI thread, not on the worker thread, so you don't even need to use Invoke() to perform UI operations (such as updating your ProgressBar).

you must use Control.Invoke for avoid cross-threading problem,but I prefer use BackgroundWorker for resolve it, create Form6 on a _field and use progressbar in ProgressChanged event for more information see this page
public void thread()
{
Form6 for6=null;
Application.OpenForms[0].Control.Invoke(delegate{
for6 = new Form6();
for6.Show();
});
}

ProgressBar while finding a file

Hi I am trying to show a progress bar while in background the code is looping till it finds a file with specific name.
I have written following code for that but the progress bar values doesn't change.
What should I change in the code below?
public partial class Form1 : Form
{
BackgroundWorker backgroundWorker1 = new BackgroundWorker();
public Form1()
{
InitializeComponent();
progressBar1.Visible = false;
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.DoWork +=
new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker1.ProgressChanged +=
new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
backgroundWorker1.RunWorkerCompleted +=
new RunWorkerCompletedEventHandler(backgroundWorker1_WorkDone);
}
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
progressBar1.Visible = true;
}
void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// Your background task goes here
for (int i = 0; i <= 100; i++)
{
// Report progress to 'UI' thread
backgroundWorker1.ReportProgress(i);
// Simulate long task
while (!File.Exists(#"C:\Users\Test.txt"))
{
continue;
}
}
}
void backgroundWorker1_ProgressChanged(object sender,
ProgressChangedEventArgs e)
{
// The progress percentage is a property of e
progressBar1.Value = e.ProgressPercentage;
}
void backgroundWorker1_WorkDone(object sender,
RunWorkerCompletedEventArgs e)
{
progressBar1.Visible = false;
}
}

The continue in your code will simply continue to the next iteration of the while(true) loop. It won't go back up to the for loop as you expect - it just keeps looping in there over and over again. If it wasn't a background worker, it'd hang your entire program. Since it is, it just hangs that thread. I expect that one CPU core stays at 100% while this is running.
That being said, while the goal here is admirable, there's no good way to accomplish it. Even if you fix the infinite loop, your progress bar will either "finish" at a low percentage (1%, 2%, 3%, done) or go up to 100, then stop updating, but without the file yet existing.

How Change A Label's Text In A Timer's Tick (GUI Is Busy)

i have a strange situation.
please see the backgroundWorker5_RunWorkerCompleted event:
private void backgroundWorker5_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
btnStartAdventures.Text = "Start Adventure";
btnStartAdventures.Enabled = true;
if (e.Error != null)
{
MessageBox.Show(e.Error.Message);
return;
}
if (e.Cancelled)
{
lblStatusValueInAdventures.Text = "Cancelled...";
}
else
{
lblStatusValueInAdventures.Text = "Completed";
timer1.Enabled = true;
timer1.Start();
// MessageBox.Show("start timer");
Thread.Sleep((int.Parse(txtDelayInAdventures.Text)) * 60000);
//MessageBox.Show("end timer");
timer1.Enabled = false;
timer1.Stop();
lblTimer.Text = "0";
btnStartAdventures.PerformClick();
}
}
and that Timer is :
private void timer1_Tick(object sender, EventArgs e)
{
this.Invoke(new MethodInvoker(delegate { lblTimer.Text = (int.Parse(lblTimer.Text) + 1).ToString(); }));
}
but this timer can not change lblTimer's Text.
how can i fix this problem?
EDIT:
that Thread.Sleep is necessary and i can not remove it.
i want a loop that never ends and those codes are for that.
thanks in advance

As requested;
What do you mean by "a loop that never ends"? A Thread.Sleep on the UI thread (RunWorkerCompleted event executes on the UI thread) will effectively freeze the UI thread, which means that no interaction with the UI thread will be shown.
Comments:
What are you trying to achieve? As far as I can guess, you are doing
some work in a background thread - backgroundWorker5 - (the UI thread
is responsive). When backgroundWorker5 is finished you want to start a
timer and display a counter in a label while the UI is still
responsive (for somebody to stop the timer maybe?). Something like
that? – Mario 3 mins ago edit
yes you are right. i want a loop and it never stops until a user click
cancel button. – MoonLight 1 min ago
So, try something like this:
int time = 0;
private void backgroundWorker5_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
btnStartAdventures.Text = "Start Adventure";
btnStartAdventures.Enabled = true;
if (e.Error != null)
{
MessageBox.Show(e.Error.Message);
return;
}
if (e.Cancelled)
{
lblStatusValueInAdventures.Text = "Cancelled...";
}
else
{
lblStatusValueInAdventures.Text = "Completed";
timer1.Interval = 1000; //<--- Tick each second, you can change this.
timer1.Enabled = true;
timer1.Start();
// MessageBox.Show("start timer");
}
}
private void timer1_Tick(object sender, EventArgs e)
{
lblTimer.Text = (time + 1).ToString();
}
private void button_Cancel_Click(object sender, EventArgs e)
{
//MessageBox.Show("end timer");
timer1.Enabled = false;
timer1.Stop();
lblTimer.Text = "0";
btnStartAdventures.PerformClick();
}

Thread.Sleep
There's your problem.
Never call Thread.Sleep in a UI thread; it will freeze the UI.
Get rid of that, and it will work fine.
You can put the rest of the work in the timer callback.
You can also use C# 5 async to make this much simpler.

You have to refresh item.
lblTimer.Refresh()
and also you could refresh form
frmName.Refresh();
and make thread to sleep 0 milliseconds that gives space for other processes.