progress bar using backgroundworker - c#

There have been a bunch of questions on how to implement a progress bar and I believe I have been through all of them and I still don't know why my progress bar won't work.
Well, it seems to work only after the operation is done, which is of course not what I want. I want the progress bar to work as the main operation is doing its thing.
My code is pretty long and painful so I'm going to simplify it to make it as basic as possible.
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
//Main UI Operation
}
private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
for (int i = 1; i <= 100; i++)
{
// Wait 100 milliseconds.
Thread.Sleep(100);
// Report progress.
backgroundWorker1.ReportProgress(i); }
}
private void BackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
Like I said, I only see the progress bar start after my main UI operation.
WorkerReportsProgress is set to True.
Minimum and Maximum are 0 and 100 respectively.
I feel like this might be a lack of understanding on Threads.

I tested the same code as you and found it worked. Did you forget to change the WorkerReportesProress property to True?

Related

c# Taskbar Progress Bar, getting value from Windows Media Player currentMedia.currentPosition

What I tried to was getting the value in the following way, which didn't work:
private void listBox1_MouseDoubleClick(object sender, MouseEventArgs e)
{
TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.Normal);
axWindowsMediaPlayer1.Ctlcontrols.play();
axWindowsMediaPlayer1.Ctlcontrols.currentItem =
axWindowsMediaPlayer1.currentPlaylist.Item[listBox1.SelectedIndex];
backgroundWorker2.RunWorkerAsync();
}
private void backgroundWorker2_DoWork(object sender, DoWorkEventArgs e)
{
double val = 100*axWindowsMediaPlayer1.Ctlcontrols.currentPosition/axWindowsMediaPlayer1.currentMedia.duration;
TaskbarManager.Instance.SetProgressValue((int)val,100);
}
I am also not sure, where would I put the line for stopping the progress, but I guess it is a bit early to think about it, since I can't get the progress to work anyway.
Is the problem in how I used the backgroundWorker or in how I update the value, or something else?
Thanks in advance,
~~hlfrmn
EDIT:
private void TaskbarProgressValueDeterminator()
{
TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.Normal);
while (axWindowsMediaPlayer1.Ctlcontrols.currentPosition < axWindowsMediaPlayer1.currentMedia.duration)
{
TaskbarManager.Instance.SetProgressValue((int)(100 * axWindowsMediaPlayer1.Ctlcontrols.currentPosition / axWindowsMediaPlayer1.currentMedia.duration), 100);
}
TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.NoProgress);
}
The background worker will update the progress only once. I expect you need to put in a while loop or a timer to update the progress repeatedly while the track is playing.

Running a BackgroundWorker continuously

I need to be able to continuously run my BackgroundWorker. The DoWork event contains a pool threaded process and the OnComplete updates my UI.
I have not been able to find a way to infinitely loop the BackgroundWorker.RunWorkerAsync() method without the whole program freezing. Any help would be greatly appreciated.
You have to make a loop in your DoWork-Method. To update your UI you shoud use the ProgressChanged-Method. Here is a small example how this can look like
public Test()
{
this.InitializeComponent();
BackgroundWorker backgroundWorker = new BackgroundWorker
{
WorkerReportsProgress = true,
WorkerSupportsCancellation = true
};
backgroundWorker.DoWork += BackgroundWorkerOnDoWork;
backgroundWorker.ProgressChanged += BackgroundWorkerOnProgressChanged;
}
private void BackgroundWorkerOnProgressChanged(object sender, ProgressChangedEventArgs e)
{
object userObject = e.UserState;
int percentage = e.ProgressPercentage;
}
private void BackgroundWorkerOnDoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = (BackgroundWorker) sender;
while (!worker.CancellationPending)
{
//Do your stuff here
worker.ReportProgress(0, "AN OBJECT TO PASS TO THE UI-THREAD");
}
}
I have done this in the past when needing something to run in the background.
If you try to run the backgroundworker while it is running, you will get an excpetion!
That is why i make the BackGroundWorker start itself when it is done in the completed event.
And then it will loop forever.
private void Main_Load(object sender, EventArgs e)
{
// Start Background Worker on load
bgWorker.RunWorkerAsync();
}
private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
Thread.Sleep(1000); // If you need to make a pause between runs
// Do work here
}
private void bgCheck_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// Update UI
// Run again
bgWorker.RunWorkerAsync(); // This will make the BgWorker run again, and never runs before it is completed.
}
timer.interval=60000 // 1 min
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
try
{
//Do something
}
catch
{
}
}
on backgroundworker completed event, just start background worker again
If your program is freezing, it may be because your infinitely looping background worker thread is spinning, using 100% CPU. You haven't said why you need it to run in an infinite loop, but you could start by putting a Thread.Sleep in that loop.

C# Threading, 1st Task DoSomething, 2nd Task update a WinFormLabel (Realtime)?

Lets say I have Task 1:
private void Task1()
{
//Here is some Code, could be any "longer" Task -
//For Example: Grab all words from a .txt File and fill in a List<String>
}
Then I have an other Task 2:
private void Task2(string word)
{
//So lets say theres a Label on my WinForm..
//Now While Task1 is grabbing the words, Task2 should fill a Label
//with the added 'word' (parameter) - (Task2 will be called from Task1
}
Actually I don't know how to make this possible, or whats the best way. On the UI I should be able to see the Label.Text changing (every word).. So I need to make a second Thread? How could I do this? Maybe someone could help me, cheers
UPDATE:
I tried it now with the Backgroundworker, but something seems to be false.. its actually not working, nothing happens on the form
Code:
public void CreateAndSaveAMatch(DateTime date) //That method is being called several times
{
//HERE IS CODE, WHICH CREATES AND SAVES A MATCH
// Start the asynchronous operation.
backgroundWorker1.RunWorkerAsync(date);
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
backgroundWorker1.ReportProgress(0, Convert.ToDateTime(e.Argument).ToShortDateString());
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
label1.Text = (string)e.UserState; //here on the Label I would like to show the Date
}
Ok, try this. This is a simple example that will show you how to solve your problem using BackgroundWorker. Also note that there are many other solutions. To use this example create a Form in a new project that only has a button and a label. Also note that this is a supplement of the other answers which were correct.
public partial class Form1 : Form
{
BackgroundWorker createAndSaveAMatchBGW;
public Form1()
{
InitializeComponent();
createAndSaveAMatchBGW = new BackgroundWorker();
createAndSaveAMatchBGW.DoWork += new DoWorkEventHandler(createAndSaveAMatchBGW_DoWork);
createAndSaveAMatchBGW.ProgressChanged += new ProgressChangedEventHandler(createAndSaveAMatchBGW_ProgressChanged);
createAndSaveAMatchBGW.RunWorkerCompleted += new RunWorkerCompletedEventHandler(createAndSaveAMatchBGW_RunWorkerCompleted);
createAndSaveAMatchBGW.WorkerReportsProgress = true;
}
private void button1_Click(object sender, EventArgs e)
{
createAndSaveAMatchBGW.RunWorkerAsync(DateTime.Now);
}
void createAndSaveAMatchBGW_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show("BackgroundWorker finished");
}
void createAndSaveAMatchBGW_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
label1.Text = ((DateTime)e.UserState).ToString("ss");
}
void createAndSaveAMatchBGW_DoWork(object sender, DoWorkEventArgs e)
{
//BackgroundWorker does something for a 10 seconds, each second it Reports
BackgroundWorker bgw = (BackgroundWorker)sender;
DateTime dt = (DateTime) e.Argument;
for (int i = 0; i < 10; i++)
{
Thread.Sleep(1000);
dt = dt.AddSeconds(1);
bgw.ReportProgress(0, dt);
}
}
}
And if you report from CreateAndSave... method only once per its execution, then you can use this code:
BackgroundWorker createAndSaveAMatchBGW;
public Form1()
{
InitializeComponent();
createAndSaveAMatchBGW = new BackgroundWorker();
createAndSaveAMatchBGW.DoWork += new DoWorkEventHandler(createAndSaveAMatchBGW_DoWork);
createAndSaveAMatchBGW.RunWorkerCompleted += new RunWorkerCompletedEventHandler(createAndSaveAMatchBGW_RunWorkerCompleted);
}
private void button1_Click(object sender, EventArgs e)
{
createAndSaveAMatchBGW.RunWorkerAsync(DateTime.Now);
}
void createAndSaveAMatchBGW_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
label1.Text = ((DateTime)e.Result).ToString();
}
void createAndSaveAMatchBGW_DoWork(object sender, DoWorkEventArgs e)
{
DateTime dt = (DateTime) e.Argument;
//you do something with your DateTime
dt = dt.AddDays(10);
e.Result = dt;
}
Use BackgroundWorker for reporting progress from first task. Drag this component from toolbox to your form, and subscribe to DoWork and ProgressChanged events. Also set property WorkerReportsProgress to true. Then start you first task asynchronously:
// this will execute code in `DoWork` event handler
backgroundWorker1.RunWorkerAsync();
Next - use userState object to pass processed words:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// grab words in a loop and report progress
backgroundWorker1.ReportProgress(0, word);
}
And last step - update label in ProgressChanged event handler
void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
label1.Text += (string)e.UserState; // this is your grabbed word
}
The simplest way to achieve this kind of thing is using BackgroundWorker.
http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx
BackgroundWorker automatically handles thread marshalling and provides events that allow you to update the UI. The event handlers run on the UI thread.
The things you do in Task1 could be moved into a BackgroundWorker, and the updates to the UI that you propose to do in Task2 can actually be in response to progress events from BackgroundWorker.
ProgressChangedEventArgs provides for user-defined data that could hold the current word.
However, Winforms (and indeed pretty much any UI) will not be able to keep up with a separate CPU thread just loading words from a file if you intend to show every word you load.
Task1 could be started on a separate thread.
You wouldn't actually need a Task2 unless there was some complex logic being performed to update the TextBox. You you really need to do is use TextBox.Invoke() to invoke the update on the UI Thread from Task1.

C# UI Thread Unresponsive

I have a function that adds a lot of files to a collection and does a lot of actions on each of them.
This causes the program (main thread) to become unresponsive.
How can I determine the cause and address the problem?
Use the BackgroundWorker object. You can inform the user with the progress of the operation by using the ReportProgress and ProgressChanged event.
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
private void Form1_Load(object sender, EventArgs e)
{
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.RunWorkerAsync();
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// .. stuff that takes long
backgroundWorker1.ReportProgress(10);
// .. stuff that takes long
backgroundWorker1.ReportProgress(20);
// .. stuff that takes long
backgroundWorker1.ReportProgress(100);
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// Done !
}
Use another thread.
Thread t = new Thread(new ThreadStart( () => {
IntensiveCalculationCode();
}));
t.Start();
You can also invoke the UI thread from inside the thread by invoking the dispatcher. They are not exactly the same on Windows Forms and WPF though.

Pause and Resume a For-Loop in C#

I'm working on a windows App in C#, I have a for-loop which update something in a loop, and I have 3 buttons on the form named "Stop,Pause,Resume". So the purpose is as same as the buttons named. Does anyone know how to do this?
Here is the Loop
private void btnCompleteAuto_Click(object sender, EventArgs e)
{
setGeneralValue();
for (int i = 1; i <= autoGridView.Rows.Count - 1; i++)
{
if (SRP == "Pause") // this is what I was thinking but it won't work
{ // it will step into end-less loop
do // how to stop this loop on "Resume" button click
{
}while(SRP!="Resume")
}
car = false;
try
{
MemberID = Convert.ToInt64(autoGridView.Rows[0].Cells["Member_ID"].Value);
DispID = Convert.ToString(autoGridView.Rows[0].Cells["Disp_Id"].Value);
Mobile = Convert.ToString(autoGridView.Rows[0].Cells["Mobile"].Value);
DueDate = Convert.ToString(autoGridView.Rows[0].Cells["Due_Date"].Value);
}
catch (Exception)
{
MessageBox.Show("Row Not Found");
}
AutoRecharge(network_name, pack_name, Mobile, Mobile, Convert.ToString(autoGridView.Rows[0].Cells["Rck_Amt"].Value), vendor_id, vendor_pwd, pack_id, oxinetwork_id);
autoGridView.Rows.RemoveAt(0);
}
}
Here are the 3 button events in which I'm setting a variable
private void btnPause_Click(object sender, EventArgs e)
{
SRP = "Pause";
}
private void btnStop_Click(object sender, EventArgs e)
{
SRP = "Stop";
autoGridView.DataSource = "";
}
private void btnResume_Click(object sender, EventArgs e)
{
SRP = "Resume";
}
The reason this doesn't work as you expect is this:
A Windows Forms application uses a single UI thread, which continually processes incoming messages from a queue. Any event handlers you attach to the events of a Windows Forms control get sent to this queue and processed by the UI thread as quickly as possible.
Your btnCompleteAuto_Click is one such handler. Once it starts, nothing else will be processed by the UI thread until it exits. Thus any other handlers you attach to other events (btnPause_Click, btnStop_Click, etc.) must wait their turn, as they will run on the same (UI) thread.
If you want pause/resume functionality, this has to be achieved on a separate thread.
A possible way to implement it might be to use a BackgroundWorker, as suggested by saurabh.
Here is a rough sketch of what your updated code might look like (I have not even attempted to compile this, let alone debug it; it's intended only as a basic outline of how you might accomplish this functionality).
You need to be aware, however, that accessing UI controls directly from a non-UI thread is a no-no. Use a mechanism such as the BackgroundWorker.ProgressChanged event to handle any UI updates that you need to happen based on activity on a non-UI thread.
ManualResetEvent _busy = new ManualResetEvent(false);
private void btnCompleteAuto_Click(object sender, EventArgs e)
{
if (!backgroundWorker.IsBusy)
{
_busy.Set();
btnAutoCompleteAuto.Text = "Pause";
backgroundWorker.RunWorkerAsync();
}
else
{
_busy.Reset();
btnAutoCompleteAuto.Text = "Resume";
}
btnStop.Enabled = true;
}
private void btnStop_Click(object sender, EventArgs e)
{
_busy.Set();
backgroundWorker.CancelAsync();
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
// for (something)
// {
_busy.WaitOne();
if (backgroundWorker.CancellationPending)
{
return;
}
// Do your work here.
// }
}
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
_busy.Reset();
btnAutoCompleteAuto.Text = "Start";
btnStop.Enabled = false;
}
After Reading your actual requirement in our comment , i would suggest that use Background worker class which supports cancellation of running process.
See here

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