C#

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            button1.Text = "processing";
            int sum = 0;
            for (int i = 0; i <= 100; i++)
            {
                Thread.Sleep(100);
                sum = sum + i;
                backgroundWorker1.ReportProgress(i);
                if (backgroundWorker1.CancellationPending)
                {
                    e.Cancel = true;
                    backgroundWorker1.ReportProgress(0);
                    return;
                }
            }
            e.Result = sum;
        }


        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
            label1.Text = e.ProgressPercentage + "%";

        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled)
            {
                label1.Text = "Process canceled";
            }
            else if (e.Error != null)
            {
                label1.Text = e.Error.Message;
            }
            else
            {
                label1.Text = "Result: " + e.Result.ToString();
            }

        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (!backgroundWorker1.IsBusy)
            {
                backgroundWorker1.RunWorkerAsync();
            }
            else
            {
                MessageBox.Show("Busy processing!. Please wait...");
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy)
            {
                backgroundWorker1.CancelAsync();
            }
            else
            {
                label1.Text = "No operation is running to cancel.";
            }
        }
    }

<pre lang="C#"> private void barButtonItem5_ItemClick(object sender, ItemClickEventArgs e)
        {
            backgroundWorker1.RunWorkerAsync();
        }

        private void backgroundWorker1_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
        {
            IWorkbook workbook = spreadsheetControl.Document;
            Worksheet worksheet = workbook.Worksheets.ActiveWorksheet;
            CellRange range = worksheet.GetDataRange();
            int LastRow = range.BottomRowIndex;
            var keys = new List<string>();
            var values = new List<int>();

            //The line below shows progress animation
            progressPanel1.Visible = true;

            for (int i = 0; i < LastRow + 1; i++)
            {
                if (worksheet.Cells[i, 10].DisplayText == "خاتمه یافته")
                {
                    keys.Add(string.Join(",", worksheet.Cells[i, 28].DisplayText, worksheet.Cells[i, 0].DisplayText, worksheet.Cells[i, 9].DisplayText,
                    worksheet.Cells[i, 15].DisplayText, worksheet.Cells[i, 31].DisplayText));
                    values.Add((int)worksheet.Cells[i, 32].Value.NumericValue);
                }
            }
            var mydic = new Dictionary<string, int>();
            for (int i = 0; i < keys.Count; i++)
            {
                if (mydic.ContainsKey(keys[i]))
                {
                    mydic[keys[i]] += values[i];
                }
                else
                {
                    mydic.Add(keys[i], values[i]);
                }
            }

            if (worksheet.HasData)
            {
                if (workbook.Worksheets.Contains("Summarized") == false)
                {
                    workbook.Worksheets.Add().Name = "Summarized";
                }
                //or
                //workbook.Worksheets.Add("Summarize")
                Worksheet ws_summarized = workbook.Worksheets["Summarized"];
                ws_summarized.Clear(workbook.Worksheets["Summarized"].GetUsedRange());
                keys.Clear();
                values.Clear();

                foreach (var item in mydic.Keys)
                {
                    keys.Add(item);
                }
                foreach (var item in mydic.Values)
                {
                    values.Add(item);
                }

                for (int i = 0; i < mydic.Count; i++)
                {
                    string text = keys[i];
                    string[] rewrite = text.Split(',');

                    workbook.Worksheets["Summarized"].Cells[i, 0].SetValue(rewrite[0]);
                    workbook.Worksheets["Summarized"].Cells[i, 1].SetValue(rewrite[1]);
                    workbook.Worksheets["Summarized"].Cells[i, 2].SetValue(rewrite[2]);
                    workbook.Worksheets["Summarized"].Cells[i, 3].SetValue(rewrite[3]);
                    workbook.Worksheets["Summarized"].Cells[i, 4].SetValue(rewrite[4]);
                }
                for (int i = 0; i < mydic.Count; i++)
                {
                    int text = values[i];

                    workbook.Worksheets["Summarized"].Cells[i, 5].SetValue(text);
                }
            }
            else
            {
                MessageBox.Show("خطای داده ورودی", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

System.InvalidOperationException: 'Cross-thread operation not valid: Control 'spreadsheetFormulaBarPanel' accessed from a thread other than the thread it was created on.'

progressPanel1.Visible = true;

System.InvalidOperationException: 'This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.'

backgroundWorker1.RunWorkerAsync();