Develop Reference

How to use progressbar.value property at different locations of program

I need to use progressbar.value property at different locations. But the problem is, while executing it shows only maximum value given. I need to stop at 25% and 75% and after some delay, 100%. How can I overcome this problem. Thanks in Advance...
C#
namespace ProgressBarWindowForm
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void Form1_Load(object sender, System.EventArgs e)
{
label1.Hide();
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;
}
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Value = 25;
if (progressBar1.Value == 25)
{
label1.Show();
label1.Text = "Process Complete 25%";
}
progressBar1.Value = 75;
if (progressBar1.Value == 75)
{
label1.Show();
label1.Text = "Process Complete 75%";
}
}
}
}
Progressbar control name is progressBar1,
Label name is label1 and
Button name is button1
When I Clicked the Button, progressbar value is directly filling with 75%. I want to stop it at 25% and after some delay it should fill 75% and then 100%...Can anyone help..Can I use "progressBar1.value" only Once or as many times I need?

try this,Drag and drop background worker in windows form
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
backgroundWorker1.WorkerReportsProgress = true;
// This event will be raised on the worker thread when the worker starts
backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
// This event will be raised when we call ReportProgress
backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
}
private void button1_Click(object sender, EventArgs e)
{
// Start the background worker
backgroundWorker1.RunWorkerAsync();
}
// On worker thread so do our thing!
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
if (label1.InvokeRequired)
{
label1.Invoke(new MethodInvoker(delegate
{
label1.Show();
label1.Text = "Process Complete " + progressBar1.Value + "%";
}));
}
if (progressBar1.Value == 25 || progressBar1.Value == 75)
{
System.Threading.Thread.Sleep(1000);
}
System.Threading.Thread.Sleep(100);
}
}
// Back on the 'UI' thread so we can update the progress bar
void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
// The progress percentage is a property of e
progressBar1.Value = e.ProgressPercentage;
}
}

Use a Timer to update the progress bar after a delay:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
timer.Tick += Timer_Tick;
timer.Interval = 1000; // delay: 1000 milliseconds
}
Timer timer = new Timer();
private void Timer_Tick(object sender, EventArgs e)
{
if (progressBar1.Value == 100)
{
timer.Stop();
return;
}
progressBar1.Value += 25;
}
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Value = 25;
timer.Start();
}
}

Its simple to update progressBar values in button click, you can initialize the properties in the page load or else use the designer, in page load it would be like the following:
private int ProgressPercentage = 10;
public void Form1_Load(object sender, System.EventArgs e)
{
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;
progressBar1.Value = 0;
}
So the initialization completed, now you can code the button click like the following, through which you can update the progress bar in every button click:
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Value += ProgressPercentage;
label1.Text = String.Format("Process Complete {0}%",progressBar1.Value);
}
If you want the update to be happens automatically in a particular interval means you can make use of a timer and enable the timer in the button click. Here you can find a similar thread which can be used to implement timer to your scene.
Update as per your comment, calling a delay will not be a best practice, you can make use a timer here as like the following:
System.Windows.Forms.Timer proTimer = new System.Windows.Forms.Timer();
private void Form1_Load(object sender, EventArgs e)
{
proTimer.Interval = 1000;
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;
progressBar1.Value = 0;
proTimer.Tick += new EventHandler(proTimer_Tick);
}
private void button1_Click(object sender, EventArgs e)
{
proTimer.Enabled = true;
proTimer.Start();
}
// Timer event
void proTimer_Tick(object sender, EventArgs e)
{
progressBar1.Value += ProgressPercentage;
label1.Text = String.Format("Process Complete {0}%",progressBar1.Value);
if (progressBar1.Value == 100)
{
proTimer.Stop();
proTimer.Enbled = false;
}
}

You need to add a delay inbetween the changes. As of now, the button advance the bar to 25, sets the label, then advances the bar to 75 without pausing.
System.Threading.Thread.Sleep(n); will sleep n milliseconds, which you will need after the statement setting the 25 percent marker.
EDIT
If you want it the value to only progress on a button click, you will need to check the value of the progress bar before you advance it.
In pseudo code, something like:
onclick() {
if (progress == 0) {
progress = 25
label = the25MarkText
} else if (progress == 25) {
progress = 75
label = the75MarkText
}
}

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 do I use backgroundworker in this instance?

I've a question on how the backgroundworker would actually work. I'm not too sure how it would work with different methods.
So for example I have the following code (adapted from http://broadcast.oreilly.com/2010/06/understanding-c-using-backgrou.html for illustration purposes):
private void getDateTime()
{
DateTime startTime = DateTime.Now;
double value = Math.E;
while (DateTime.Now < startTime.AddMilliseconds(100))
{
value /= Math.PI;
value *= Math.Sqrt(2);
}
}
private backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
for(int i=0; i <= 100; i++)
{
getDateTime();
backgroundWorker1.ReportProgress(i);
}
}
This would continually calculate the DateTime using the backgroundworker thread. Now I'm assuming that the for-loop within the backgroundworker's DoWork method would run the calculation, report the progress, and then reiterate the loop (please do correct me if I've misunderstood).
Now assuming I have another method, which parses a (presumably large) DataTable and returns another DataTable, using it in the backgroundworker would mean I'd be parsing the DataTable over and over (theoretically. again, correct me if I'm wrong)? If this is how the program would flow, is there a more efficient method to achieve the DataTable parsing without having to reiterate the loop, but still being able to use backgroundworker?
This is intended for a Windows Form, and the UI tends to freeze up when I parse the DataTable(s). I've heard that backgroundworker could help me get around the freezing of the UI, but I find it highly inefficient to have to re-parse the entire DataTable over, and over. However I'm not sure of any other way I can report progress without a for-loop either.
EDIT:
I've figured out a temporary solution. It works, but I still have no way of reporting progress.
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
int rows = (int)e.Argument;
int count = 0;
t3 = runComparison();
for (int i = 0; i <= rows; i++)
{
count++;
int current = count / rows;
backgroundWorker1.ReportProgress(current * 100);
}
e.Result = t3;
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Error != null)
{
MessageBox.Show("An unexpected error has occurred. Please try again later.", "ERROR!", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
dataGridView1.DataSource = e.Result;
}
}
I'm aware my for-loop doesn't do anything. However, the "runComparison" already consumes a lot of time. As such, progress doesn't get reported until an entire run-through if it's in the for-loop. Alternatively, maybe I could use a label or messagebox instead of the progress bar. Not too sure how I'm supposed to achieve this.

Try to do this:
//make sure background worker report progress
backgroundWorker1.WorkerReportsProgress = True;
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
progressBar1.Refresh;
//if your progressbar is on a status strip, you need to refresh the status strip instead
}

I've come up with a rather inelegant solution. But it satisfies the requirement for user-friendliness so... Whatever works :P
Thanks for all the feedback, I appreciate it.
Anyway, here's the code:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
backgroundWorker1.ReportProgress(1); //to invoke ProgressChanged
t3 = runComparison(); //run intensive method
e.Result = t3; //return DataTable
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Visible = true; //display a label
textBoxProgress.Visible = true; //display the progress bar
//change the progress bar style
//the Marquee style is constantly running, so it could show users the process is working
//not too sure how to explain it, you'll have to try it out.
progressBar1.Style = ProgressBarStyle.Marquee;
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Error != null)
{
MessageBox.Show("An unexpected error has occurred. Please try again later.", "ERROR!", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
//reset the display and update the DataGridView
progressBar1.Visible = false;
textBoxProgress.Visible = false;
progressBar1.Style = ProgressBarStyle.Blocks;
dataGridView1.DataSource = e.Result;
}
}

progressbar not progressing using backgroundworker

I am using a background worker to update some tables in sqlserver. the progressbar max is getting set to the correct value, the progressbar value is being incremented, the backgroundworker progresschanged is being called correctly with correct value, yet the bar is not progressing.
here is the code for the form
in the background_dowork method there is a loop which calls updateProgressBarValue which works with correct values.
public InterfaceConvertLonLat()
{
InitializeComponent();
Shown += new EventHandler(Form1_Shown);
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
}
public void ConvertLonLat_Load(object sender, EventArgs e)
{
}
public void updateProgressBarValue()
{
progressBar1.Value++;
backgroundWorker1.ReportProgress(progressBar1.Value);
}
public void setProgressBarMax(int max)
{
progressBar1.Maximum = max;
MessageBox.Show("setprogressbarmax " + max);
}
public void Form1_Shown(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
}
public void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
convert.OSGB36ToWGS84("paf");
}
public void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
here is the loop contained in another class which calls updateprogressbarvalue, this is being fired and as stated backgroundworker1_progressChanged is being fired but the bar is not moving.
con.setProgressBarMax(address.Tables[0].Rows.Count);
foreach (DataRow LonLat in address.Tables[0].Rows)
{
con.updateProgressBarValue();
Double lon = 0;
Double lat = 0;
lat = Convert.ToDouble(LonLat["LTO"]);
lon = Convert.ToDouble(LonLat["LGO"]);
LocalToWGS84(ref lat, ref lon, OGB_M);
cmd1.Parameters["#LTW"].Value = lat;
cmd1.Parameters["#LGW"].Value = lon;
string dbQuery1 = "update " + tableName + " set LTW = #LTW, LGW = #LGW";
cmd1.CommandText = (dbQuery1);
cmd1.CommandType = CommandType.Text;
cmd1.Connection = conn;
cmd1.ExecuteNonQuery();
}
}
catch (Exception e)
{
MessageBox.Show("error converting: " + e.Message);
}
finally
{
conn.Close();
}

When reporting progress you need to fire an event from the background worker to tell the progressbar it needs updating. This can be done using the below:
backgroundWorker1.ReportProgress(10);
Change the value to what you need to demonstrate increased progress in your code. The progress changed event will mostly run on the same thread as your GUI so you should have no cross thread issues. One exception is if your form is being called from Excel via addin in which case Excel will be on the main thread.

You've got a number of issues - Your UpdateprogressBarValue() just increases the value of the progress bar but doesn't keep track of how many times its been called / what the current value is - so if you call it 101 times (assuming a range of 0-100), you'll get an OutOfRangeException
Your DoWork() method doesn't seem to call the update at all (either directly or by raising an event).
You can use events to do this but you're better off using delegates or perhaps anonymous functions. Something like...
public void setProgress(int value) {
progressBar1.invoke(delegate{ progressBar1.Value = value; }
}
then just call setProgress(0) through setProgress(progressBar1.MaxValue) from your DoWork() method

The following is seriously wrong:
public void updateProgressBarValue()
{
progressBar1.Value++; // not thread-safe
backgroundWorker1.ReportProgress(progressBar1.Value);
}
ReportProgress() is intended to be called form DoWork, it should not even read a Control property.
You should maintain a counter in the foreach loop and feed that to the progress mechanism.
Now this does not directly indicate why it doesn't move but you do not have a Completed handler. Are you sure the process finishes at all?
If an exception escapes your DoWork you will never know what happened.

private void Form1_Load(object sender, System.EventArgs e)
{
// Start the BackgroundWorker.
backgroundWorker1.RunWorkerAsync();
}
private void backgroundWorker1_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 backgroundWorker1_ProgressChanged(object sender, progress e)
{
// Change the value of the ProgressBar to the BackgroundWorker progress.
progressBar1.Value = e.ProgressPercentage;
// Set the text.
this.Text = e.ProgressPercentage.ToString();
}

I think this might be caused by the fact that the UI in windows forms is running in its own thread/context. In this case you probably need to use Invoke to make adjustments to the UI.
Something like this:
public void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
Invoke(new ProgressDelegate(UpdateProgress), e.ProgressPercentage);
}
delegate void ProgressDelegate(decimal value);
private void UpdateProgress(decimal value)
{
progressBar1.Value = value;
}

C# BackgroundWorker - how should i get rid of DoEvents

I'm trying to figure out the best way to handle a backgroundworker that is triggered off radio button clicks. I created a very simple form with 3 radio buttons and a label. Each of the radio buttons share the same event radioButton_CheckedChanged. If the event completes then I update the label to "Complete". If you click another radio button before the event completes then update label to Cancelled. Below is the code i have written in this quick example. Although the application tends to run as expected my concern is the use of Application.DoEvents. What are my alternatives to this. For obvious reasons i can't sleep while IsBusy. Am I going about this all wrong or is there a better way to do this?
Thanks, poco
private void radioButton_CheckedChanged(object sender, EventArgs e)
{
RadioButton rb = sender as RadioButton;
if (rb.Checked)
{
if (backgroundWorker1.IsBusy)
{
backgroundWorker1.CancelAsync();
while (backgroundWorker1.IsBusy)
Application.DoEvents();
}
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
for (int i = 0; i < 100 && !worker.CancellationPending; ++i)
Thread.Sleep(1);
if (worker.CancellationPending)
{
e.Cancel = true;
return;
}
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
label1.Text = "Canceled";
else
label1.Text = "Complete";
}

You should move the code that must run when the BackgroundWorker completes into the RunWorkerCompleted hander. In pseudo-code:
private void radioButton_CheckedChanged(object sender, EventArgs e)
{
// ...
if (backgroundWorker1.IsBusy)
{
backgroundWorker1.CancelAsync();
addJobToQueue(); // Don't wait here, just store what needs to be executed.
} else {
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled) {
label1.Text = "Canceled";
}
else {
label1.Text = "Complete";
}
// We've finished! See if there is more to do...
if (thereIsAnotherJobInTheQueue())
{
startAnotherBackgroundWorkerTask();
}
}

DoEvents is not supposed to be taken so casually. There are better ways. One of the very nice ones is described here in SO. This answer is probably best for you.
Hence your solution becomes:
private AutoResetEvent _resetEvent = new AutoResetEvent(false);
private void radioButton_CheckedChanged(object sender, EventArgs e)
{
RadioButton rb = sender as RadioButton;
if (rb.Checked)
{
if (backgroundWorker1.IsBusy)
{
backgroundWorker1.CancelAsync();
_resetEvent.WaitOne(); // will block until _resetEvent.Set() call made
}
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
for (int i = 0; i < 100 && !worker.CancellationPending; ++i)
Thread.Sleep(1);
if (worker.CancellationPending)
{
e.Cancel = true;
}
_resetEvent.Set();
}