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BackgroundWorker - reporting progress with "sub tasks"

A WinForms application with a custom control, LabelProgressBar, which has the ability to display both progress and some descriptive text and/or percentage completion. This is done by calling LabelProgressBar.statusInProgress(string message, int percentageCompletion).
One usage of this is as follows:
private void import_begin(System.Object sender, System.ComponentModel.DoWorkEventArgs args)
{
// first unpack the arguments
System.Object[] arguments = (System.Object[])args.Argument;
System.String filename = (System.String)arguments[0];
System.String why = (System.String)arguments[1];
// tasks:
// 1. read excel file and apply changes to model
// 2. gather changes and format them as XML
// 3. send request to server
// 4. commit/rollback changes
// grab the worker thread so we can report percentage progress
System.ComponentModel.BackgroundWorker worker = (System.ComponentModel.BackgroundWorker)sender;
// now do the work
#region Task1
Controller.Excel excel = new Controller.Excel(filename);
try
{
// the progress of this needs to be tracked
overall_result = excel.import_all(out modified_nodes);
}
catch (InvalidDataExcetpion invDataEx)
{
// deal with it
}
#endregion
worker.ReportProgress(25);
// complete remaining tasks...
}
The event handler for the worker reporting its progress is the following:
private void import_progress(object sender, System.ComponentModel.ProgressChangedEventArgs e)
{
Debug.WriteLine("Import percentage completion: " + e.ProgressPercentage);
labelProgressBar1.statusInProgress("Import", e.ProgressPercentage);
}
In short, the import_begin method is broken up into several "tasks". These are broken up into "subtasks". Taking the example of the import_all method:
public Command_Result import_all(out System.Collections.Generic.List<Model.Data_Node> nodes)
{
Command_Result overall_result = Command_Result.OK;
Command_Result this_result;
nodes = new System.Collections.Generic.List<Model.Data_Node>(excel.Workbook.Worksheets.Count);
Model.Data_Node destination;
// the intent is to report the progress of this particular subtask on the basis of how many worksheets have been processed in this for loop
foreach (OfficeOpenXml.ExcelWorksheet worksheet in excel.Workbook.Worksheets)
{
this_result = import_sheet(worksheet.Name, out destination);
nodes.Add(destination);
if (this_result > overall_result)
{
overall_result = this_result;
}
}
return overall_result;
}
The intent is to have this "subtask" report progress on the basis of how many sheets have been processed in the loop. Calculating a percentage for this is a trivial task, but it is not clear to me how this can be reported back to the import_begin method. When this "subtask" is completed, the overall task completion (from the POV of the import_begin method) should be 25%. Similarly for the other tasks. How can this be achieved?

import_begin don't really need to get the update, it can just call the subtasks, while also passing the BackgroundWorker, so the subtasks are responsible to directly report their progress. If "polluting" the subtasks with BackgroundWorker is unacceptable, then create a delegate to call the BackgroundWorker, so your subtasks will then call the delegate instead.
private void mainTask(object sender, DoWorkEventArgs e)
{
var worker = (BackgroundWorker)sender;
var report = new Action<int>(i => worker.ReportProgress(i)); //the delegate
smallTask1Clean(report); //this one pass the delegate
smallTask2(worker); //this one directly call background worker
worker.ReportProgress(100);
}
void smallTask1Clean(Action<int> a)
{
for (int i = 0; i < 20; i++)
{
Thread.Sleep(500);
a(i);
}
}
void smallTask2(BackgroundWorker w)
{
for (int i = 0; i < 5; i++)
{
Thread.Sleep(1000);
w.ReportProgress(i*80/5+20);
}
}
You can also insulate the subtasks from having to know their part in the larger tasks, in this case, the delegate should take two variables, the current internal progress of the subtasks and the total item it needs to process.
private void mainTask(object sender, DoWorkEventArgs e)
{
var worker = (BackgroundWorker)sender;
var preTaskProgress = 0;
var currentTaskTotalPercentage = 0;
var smarterDelegate = new Action<int, int>((current, total) =>
{
worker.ReportProgress(preTaskProgress + (current *currentTaskTotalPercentage/total));
});
currentTaskTotalPercentage = 30; //the following task will in total progressed the main task for 30%
smallTaskClean(smarterDelegate);
preTaskProgress = currentTaskTotalPercentage; //upate the main the progress before starting the next task
currentTaskTotalPercentage = 70; //the following task will in total progressed the main task for 70%
smallTaskClean(smarterDelegate);
worker.ReportProgress(100);
}
void smallTaskClean(Action<int,int> a)
{
for (int i = 0; i < 5; i++)
{
Thread.Sleep(1500);
a(i,5);
}
}

C# Label text not updating while Progress bar value is

In C# im trying to make a little game type program and im trying to make a loading bar that uses the Progress bar and the text is using a Label, for example the Progress bar is 1 - 25 and i want the label text to update while the bar is, heres an example:
private void StartLoading_Click(object sender, EventArgs e)
{
MainProgressBar.Maximum = 25;
int P = 0;
while (P < 25)
{
// Delay
System.Threading.Thread.Sleep(130);
// Increase Progress
P++;
// Set Progress Bar Value
MainProgressBar.Value = P;
// Set Text Above Progress Bar
LoadingText.Text = P + "/25";
}
}
Ps. I dont want some Huge code, i want it to be simple like this

State of the art is this snippet for you:
private void StartLoading_Click(object sender, EventArgs e)
{
const int max = 25;
var progressHandler = new Progress<int>(value=>{
LoadingText.Text = value + "/" + max;
MainProgressBar.Value = value;
});
var progress = progressHandler as IProgress<int>;
await Task.Run(() =>
{
int P = 0;
while (P < 25)
{
Thread.Sleep(130);
progress?.Report(++P);
}
}
}
This processes your long running task (Sleep in this case), in a seperate Thread and reuse the value via the Progress-Class. This way your GUI is updated in GUI-Thread as recommended and you will get the updates accordingly. Further it's not recommended to use Application.DoEvents();, because there are many pitfalls you have to know about.

Firing events in loop are not updating UI in sequence

I was trying to update status on UI for a Long Running Operating. I've created a demo form based application, task it have multiple rows, each row is having days and default values in each column of datagrid is 0, once computation file computes one iteration for one day it will update UI and set 1 for that day.
I am using threading, delegates and events to implement this and it is working as expected if I put Thread.Sleep(100) between two event calls. If I put "Thread.Sleep(100)" inside last nested for loop then it updates UI as expected but as soon as I remove it and run loop without sleep, then it skips some of the columns on UI and directly update last few/random columns, as you can see in attached image link(Image of output of my code without thread sleep) only last column is getting updated.
If I am not mistaken all the events are getting fired in sequence then they should update UI in sequence too but it's not happening and I don't know why. I don't want to do this Sleep thing because I have around 14 calls in actual application for UI status update and it will run under a loop so if It put sleep(100) then it will cost me a lot, is there any way to do it without SLEEP?
Image of output of my code without thread sleep
public class Class1 : IGenerate
{
public event MessageEventHandler OnMessageSending;
public void LongOperationMethod(BindingList<Status> _statusData)
{
if (OnMessageSending != null)
{
MessageEventArgs me = new MessageEventArgs();
/// Loop for 2-3 Weeks
for (; ; ){
/// Loop for 7 day
for (; ; )
{
/// Calculation on everyday
for (int j = 0; j != 1000; ++j)
{
// to do
}
me.weekNo = k;
me.DayNo = i;
OnMessageSending(me);
}
}
me.Message = "Process completed successfully...";
OnMessageSending(me);
}
else
{
throw new ArgumentException("Event hasn`t been rised, so we cannot continue working.");
}
}
}
**UI file:**
<pre><code>
public partial class Form1 : Form
{
BindingList<Status> _statusData = new BindingList<Status>();
delegate void StringParameterDelegate(string value);
Class1 cls = new Class1();
public Form1()
{
InitializeComponent();
labelProgress.Text = "";
}
private void button1_Click_1(object sender, EventArgs e)
{
for (int i = 1; i <= 2; ++i)
{
_statusData.Add(new Status { Week = "Week" + i, Day1 = 0, Day2 = 0, Day3 = 0, Day4 = 0, Day5 = 0, Day6 = 0, Day7 = 0 });
}
dataGridView1.DataSource = _statusData;
}
private void button2_Click(object sender, EventArgs e)
{
Thread t1 = new Thread(() => StartingThread(_statusData));
t1.Start();
}
void StartingThread(BindingList<Status> _statusData)
{
IGenerate generate = new Class1();
generate.OnMessageSending += new MessageEventHandler(generate_OnMessageSending);
generate.LongOperationMethod(_statusData);
}
private void generate_OnMessageSending(MessageEventArgs e)
{
int weekNo = e.weekNo;
int dayNo = e.DayNo;
this.dataGridView1.BeginInvoke(new MethodInvoker(() => dataGridView1.Rows[e.weekNo].Cells[e.DayNo + 1].Value = 1));
this.labelProgress.BeginInvoke(new MethodInvoker(() => this.labelProgress.Text = e.Message));
}
}
</code></pre>

It looks like you are sending the same instance of MessageEventArgs every time, and just updating that one instance on the background thread. This means that your event handler on the UI thread will retrieve the exact same instance of MessageEventArgs that is being updated in the loop! By the time your UI handler gets the MessageEventArgs, its .weekNo and .DayNo properties could well have been modified by the next iteration of the loop, since they are running on separate threads.
To fix this, create a new instance of MessageEventArgs every time you call OnMessageSending().
Relevant snippet:
MessageEventArgs me = new MessageEventArgs();
me.weekNo = k;
me.DayNo = i;
OnMessageSending(me);

Adding percentage text to progressbar C#

I have a method that shows when a process bar is in execution and when is successfully completed.
I worked fine, but I would like to add a percentage showing a 100% if is complete and less if it got stuck some where.
I have made several research online but I could not adapt anything to the solution that I am looking for.
This is my code:
private void progressBar()
{
int i;
progressBar1.Minimum = 0;
progressBar1.Maximum = 100;
for (i = 0; i <= 100; i++)
{
progressBar1.Value = i;
}
}
I use the method call on my execution button by calling it with the follow:
progressBar();
Thanks

I have adjust the prograssBar method with the following lines.
The solution works.
Thanks
int percent = (int)(((double)progressBar1.Value / (double)progressBar1.Maximum) * 100);
progressBar1.Refresh();
progressBar1.CreateGraphics().DrawString(percent.ToString() + "%",
new Font("Arial", (float)8.25, FontStyle.Regular),
Brushes.Black,
new PointF(progressBar1.Width / 2 - 10, progressBar1.Height / 2 - 7));

In order to implement the progress in your operation, the operation's length must be calculated first. if it's not possible, you can't show a progress bar for that operation. (maybe only a loading gif)
but if so, There is an interface (IProgress) which can help you implement the progress reports.
First thing you should know, You must do the main task on another thread, and report the progress to the UI Thread. a simple example of this work would be something like this.
Progress.cs
public class Progress<T> : IProgress<T>
{
private readonly Action<T> _progressAction;
public Progress(Action<T> action)
{
_progressAction = action;
}
public void Report(T value)
{
_progressAction?.Invoke(value);
}
}
Your code would be like this, in which the task starts after you click a button named ButtonBase
Progress<int> MyProgressObject { get; set; }
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
MyProgressObject = new Progress<int>(ProgressAction);
ThreadPool.QueueUserWorkItem(TimeConsumingTask);
}
public void TimeConsumingTask(object state)
{
for (int i = 0; i < 100; i++)
{
Thread.Sleep(100);
MyProgressBar.Dispatcher.Invoke(() => ProgressAction(i));
}
}
public void ProgressAction(int progress)
{
MyProgressBar.Value = progress;
}
I know It might look difficult but this is the proper way of doing time consuming tasks and prevent UI block

If you use it as a part of backgroundworker it works perfectly
I added a Label in the middle of the progressbar
And i added last row in my bgw_ProgressChanged method
private void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
p_bar.Value = e.ProgressPercentage;
fnameLbl.Text = e.UserState.ToString();
percentLbl.Text = "%" + (e.ProgressPercentage).ToString();
}
ProgressPercentagevalue comes from the method below
foreach (var item in filebox1)
{
System.IO.File.Move(item, Path.Combine(destdir, Path.GetFileName(item)));
++counter;
int tmp = (int)((counter* 100) / totfiles);
bgw.ReportProgress(tmp, "File transfered : " + Path.GetFileName(item));
Thread.Sleep(100);
}
Totfiles is the number of files that I get from server.
Thread.Sleep(100) let's you see for a short time what is displayed with fnameLbl.Text

int total = ;
int val = ;
double createDivider = total / 100;
int percent = val / createDivider;
this value (percent) is the right percent '%' of total

How to set value of progress bar

I have written a user control using C# Winforms. In the user control, I have three textboxes:
txtStartNumber - input is of type: int.
txtEndNumber - input is of type: int.
txtQuantity - iput is of type: int. (value = txtEndNumber - txtStartNumber)
The progress bar denotes the no. of records added to the database and its total range is set to be equal to txtQuantity.
When one or more records are duplicate, the progress bar is stopped.
My questions are:
How to set the initial value of the progress bar?
How to manage the progress shown by progress bar?
How I save it to the database:
for (long i = from; i < to; i++)
{
for (int j = 0; j < (to - from); j++)
{
arrCardNum[j] = from + j;
string r = arrCardNum[j].ToString();
try
{
sp.SaveCards(r, 2, card_Type_ID, SaveDate, 2);
progressBar1.Value = j;
}
}
}

Try this:
private void StartBackgroundWork() {
if (Application.RenderWithVisualStyles)
progressBar.Style = ProgressBarStyle.Marquee;
else {
progressBar.Style = ProgressBarStyle.Continuous;
progressBar.Maximum = 100;
progressBar.Value = 0;
timer.Enabled = true;
}
backgroundWorker.RunWorkerAsync();
}
private void timer_Tick(object sender, EventArgs e) {
progressBar.Value += 5;
if (progressBar.Value > 120)
progressBar.Value = 0;
}
The Marquee style requires VisualStyles to be enabled, but it continuously scrolls on its own without needing to be updated. I use that for database operations that don't report their progress.
Here is another Progress Bar Tutorial

You can't use loop to do this with progressbar. There is a difference between running code in for, while, do...while loops or in timers. In loops code is immediately done and you can't see this, in timers you can. Even if you try to put in loops if counters, it will not works:
for(int i=a;i<b;++i)
{
if (cnt < 1000000)
{
IncrProgressBar();
cnt++;
}
else
{
cnt = 0;
}
}
If you want to use progressbar to do this then you must put in timer OnTick event code that adds data to database, and in this event increment progressbar value. It's similarly with changing form component's other properties (Text, Size, ...). If you want to see change on component you must use timers.

To change the value use:
private void timer1_Tick(object sender, EventArgs e)
{
progressBar2.Value = progressBar2.Value - 15;
}
In C#