Winforms Progress bar Does Not Update (C#)

c#

Solution

It sounds like you are blocking the UI thread - i.e. you haven't released the system to do any painting.

A hacky answer is to inject `Application.DoEvents()` into your code - but this is risky, and has problems with re-entrancy etc; and it is just a bit hacky.

A better option may be to do the processing on a `BackgroundWorker`, periodically switching to the UI thread to update things (Control.Invoke) - but this may be tricky if you are adding lots of items to a `ListView`.

Full example (although you might want to batch the UI updates - not a row at a time):

using System;
using System.ComponentModel;
using System.Threading;
using System.Windows.Forms;

class MyForm : Form
{
    BackgroundWorker worker;
    ListView list;
    Button btn;
    ProgressBar bar;
    public MyForm()
    {
        Text = "Loader";
        worker = new BackgroundWorker();
        worker.WorkerReportsProgress = true;
        worker.ProgressChanged += worker_ProgressChanged;
        worker.DoWork += worker_DoWork;
        worker.RunWorkerCompleted += worker_RunWorkerCompleted;
        list = new ListView();
        list.Dock = DockStyle.Fill;
        Controls.Add(list);
        btn = new Button();
        btn.Text = "Load";
        btn.Dock = DockStyle.Bottom;
        Controls.Add(btn);
        btn.Click += btn_Click;
        bar = new ProgressBar();
        bar.Dock = DockStyle.Top;
        Controls.Add(bar);
    }

    void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        btn.Enabled = true;
    }

    void btn_Click(object sender, EventArgs e)
    {
        worker.RunWorkerAsync();
        btn.Enabled = false;
    }


    void worker_DoWork(object sender, DoWorkEventArgs e)
    {
        for (int i = 0; i < 100; i++)
        {
            string newRow = "Row " + i.ToString();
            worker.ReportProgress(i, newRow);
            Thread.Sleep(100);
        }
    }

    void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        list.Items.Add((string)e.UserState);
        bar.Value = e.ProgressPercentage;
    }

    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new MyForm());
    }
}

Problem

In my program [C# + winforms]. I have progress bar & listview. Through one method i am performing some operations & then updating data in Listview. The no of records added is the value i am setting for ProgressBar.value property. What i want here is, According to value of progress bar, it should show its progress. However the progress bar is not getting updated. Only at the end of method execution progress bar shows entire progress i.e. 100 % Can someone help me in this regard? Thanks, Amit

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