using System.IO;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TestProgram
{
    public partial class Form1 : Form
    {
        public int currentValue;
        public int targetValue;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // set background worker values
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.WorkerSupportsCancellation = true;

            // set numericUpDown control values
            numericUpDown1.Minimum = 0;
            numericUpDown1.Maximum = int.MaxValue;
            numericUpDown1.Value = 1000;

            // init default values
            setDefaultValues();
        }

        private void setDefaultValues()
        {
            // init everything with default values
            currentValue = 0;
            targetValue = (int)numericUpDown1.Value;
            label1.Text = "0";
            progressBar1.Minimum = 0;
            progressBar1.Maximum = 100;
            progressBar1.Value = 0;
        }

        private void buttonStart_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy != true)
            {
                // re-init default values
                setDefaultValues();

                // start the background process
                backgroundWorker1.RunWorkerAsync();
            }
        }

        private void buttonStop_Click(object sender, EventArgs e)
        {
            // cancel and stop the background process
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                backgroundWorker1.CancelAsync();
            }
        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;

            // loop from 0 to targetValue
            int currentPercent = 0;
            for (int n=0; n < targetValue; n++)
            {
                // set current value
                currentValue = n;

                // check if user requested cancel
                if(worker.CancellationPending == true)
                {
                    e.Cancel = true;
                    break;
                }

                // calculate percent completed
                currentPercent = (int)(((double)n / (double)targetValue) * 100);

                // report progress
                backgroundWorker1.ReportProgress(currentPercent);

                /* for demo purposes lets slow things down by
                waiting a fraction of a second before continuing */
                System.Threading.Thread.Sleep(50);
            }
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            // update the label
            label1.Text = currentValue.ToString();

            // update the progress bar
            progressBar1.Value = e.ProgressPercentage;

        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            // see why work completed
            if(e.Error != null)
            {
                // an error happened
                label1.Text = "Error: " + e.Error.Message;
            }
            else if(e.Cancelled == true)
            {
                // user had cancelled
                label1.Text = "User Cancelled at interval # " + Convert.ToString(currentValue);
            }
            else
            {
                // process completed
                label1.Text = "Process Completed at interval # " + Convert.ToString(currentValue);
            }

            // clear the progress from the progress bar
            progressBar1.Value = 0;
        }

    }
}