Progress bar count percentage not updating correctly win c#

Question

I am trying to apply progress bar. here percentage updating not correctly. what is the problem.

progbar1.Maximum = dt.Rows.Count; // Total Records 1000  
progbar1.Minimum = 0;  
progbar1.Step = 3;    
  
foreach (DataRow DR in dt.Rows)  
{  
     progbar1.PerformStep();  
     progbar1.Value++;  
}  

Here, the initial progress percentage showing "57%". But, it support to start 0%.

While debugging it's showing "0%". but, in the front end progress bar showing "57%".

How it is possible...?

Answer 1

Hi GaniTPT,
Based on your code, there is a problem that the value of progbar1 will exceed his maximum value in the foreach loop.
And to avoid blocking the UI thread, I suggest you use BackgroundWorker to update the progress.
Here is a code example you can refer to.

private void button1_Click(object sender, EventArgs e)  
{  
    progressBar1.Maximum = dt.Rows.Count;  
    progressBar1.Value = 0;  
    progressBar1.Step = 3;  
    progressBar1.Minimum = 0;  
    backgroundWorker1.WorkerReportsProgress = true;  
    backgroundWorker1.RunWorkerAsync();     
}  
  
DataTable dt = new DataTable();  
private void Form1_Load(object sender, EventArgs e)  
{  
    for (int i = 0; i <= 1000; i++)  
    {  
        DataRow row = dt.NewRow();  
        dt.Rows.Add(row);  
    }  
}  
  
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)  
{  
    progressBar1.Value = e.ProgressPercentage;  
}  
  
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)  
{  
    var backgroundWorker = sender as BackgroundWorker;  
    for (int j = 0; j <= dt.Rows.Count; j++)  
    {  
        backgroundWorker.ReportProgress((j * progressBar1.Maximum) / dt.Rows.Count);  
  
    }  
}  

Best Regards,
Daniel Zhang

---

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Answer 2

I think that your program cannot handle the Paint event and update the appearance because it is busy with the loop or is stopped at breakpoint.

As a workaround, try executing progbar1.Update() inside the loop. This usually helps in case of standard Progress Bar.

Answer 3

Hello,

Full source is in this project on GitHub.

• First example uses a standard ProgressBar with cancellation option (written a while ago)
• Second example uses a custom Progressbar with percentage shown.
• Both examples keep the user interface responsive
• For the second example, there is a await Task.Delay(50), for real life usage change to Task.Delay(1). 50 was used to allow you to see progress and try and move the form around showing all is responsive.

Here I will focus on the custom progress bar.

private async Task ProgressbarExperiment()  
{  
    ProgressBarSpecial.Value = 0;  
    var maxValue = 10000;  
    ProgressBarSpecial.Maximum = maxValue;  
  
    for (int index = 0; index < maxValue; index++)  
    {  
        int value = ProgressBarSpecial.Value + 100;  
  
        await Task.Delay(50);  
  
        if (value > ProgressBarSpecial.Maximum)  
        {  
            ProgressBarSpecial.Value = ProgressBarSpecial.Maximum;  
            break;  
        }  
        else  
        {  
            ProgressBarSpecial.Value = value;  
        }  
    }  
  
    await Task.Delay(1000);  
  
}  
  
private async void RunButton1_Click(object sender, EventArgs e)  
{  
    await ProgressbarExperiment();  
}