title: File Copy with Progress Bar
body: <p>I used this code: </p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Windows.Forms;
  using System.IO;
  
  namespace WindowsApplication1 {
    public partial class Form1 : Form {
      // Class to report progress
      private class UIProgress {
        public UIProgress(string name_, long bytes_, long maxbytes_) {
          name = name_; bytes = bytes_; maxbytes = maxbytes_;
        }
        public string name;
        public long bytes;
        public long maxbytes;
      }
      // Class to report exception {
      private class UIError {
        public UIError(Exception ex, string path_) {
          msg = ex.Message; path = path_; result = DialogResult.Cancel;
        }
        public string msg;
        public string path;
        public DialogResult result;
      }
      private BackgroundWorker mCopier;
      private delegate void ProgressChanged(UIProgress info);
      private delegate void CopyError(UIError err);
      private ProgressChanged OnChange;
      private CopyError OnError;
  
      public Form1() {
        InitializeComponent();
        mCopier = new BackgroundWorker();
        mCopier.DoWork += Copier_DoWork;
        mCopier.RunWorkerCompleted += Copier_RunWorkerCompleted;
        mCopier.WorkerSupportsCancellation = true;
        OnChange += Copier_ProgressChanged;
        OnError += Copier_Error;
        button1.Click += button1_Click;
        ChangeUI(false);
      }
  
      private void Copier_DoWork(object sender, DoWorkEventArgs e) {
        // Create list of files to copy
        string[] theExtensions = { "*.jpg", "*.jpeg", "*.bmp", "*.png", "*.gif" };
        List&lt;FileInfo&gt; files = new List&lt;FileInfo&gt;();
        string path = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
        DirectoryInfo dir = new DirectoryInfo(path);
        long maxbytes = 0;
        foreach (string ext in theExtensions) {
          FileInfo[] folder = dir.GetFiles(ext, SearchOption.AllDirectories);
          foreach (FileInfo file in folder) {
            if ((file.Attributes &amp; FileAttributes.Directory) != 0) continue;
            files.Add(file);
            maxbytes += file.Length;
          }
        }
        // Copy files
        long bytes = 0;
        foreach (FileInfo file in files) {
          try {
            this.BeginInvoke(OnChange, new object[] { new UIProgress(file.Name, bytes, maxbytes) });
            File.Copy(file.FullName, @"c:\temp\" + file.Name, true);
          }
          catch (Exception ex) {
            UIError err = new UIError(ex, file.FullName); 
            this.Invoke(OnError, new object[] { err });
            if (err.result == DialogResult.Cancel) break;
          }
          bytes += file.Length;
        }
      }
      private void Copier_ProgressChanged(UIProgress info) {
        // Update progress
        progressBar1.Value = (int)(100.0 * info.bytes / info.maxbytes);
        label1.Text = "Copying " + info.name;
      }
      private void Copier_Error(UIError err) {
        // Error handler
        string msg = string.Format("Error copying file {0}\n{1}\nClick OK to continue copying files", err.path, err.msg);
        err.result = MessageBox.Show(msg, "Copy error", MessageBoxButtons.OKCancel, MessageBoxIcon.Exclamation);
      }
      private void Copier_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) {
        // Operation completed, update UI
        ChangeUI(false);
      }
      private void ChangeUI(bool docopy) {
        label1.Visible = docopy;
        progressBar1.Visible = docopy;
        button1.Text = docopy ? "Cancel" : "Copy";
        label1.Text = "Starting copy...";
        progressBar1.Value = 0;
      }
      private void button1_Click(object sender, EventArgs e) {
        bool docopy = button1.Text == "Copy";
        ChangeUI(docopy);
        if (docopy) mCopier.RunWorkerAsync();
        else mCopier.CancelAsync();
      }
    }
  }
  </code></pre>
  
  <p>posted <a href="http://social.msdn.microsoft.com/forums/en-US/Vsexpressvcs/thread/a285bdb9-6838-48f3-b8ed-1bf0156f8c51" rel="noreferrer">here</a> (the one that <em>nobugz</em> posted) in copying files and displaying the status in progress bar. </p>
  
  <p>I wanted to continuously increment the value of the progress bar while copying, especially large files. What happens in this sample code is that the value in progress bar stops on every file copied and after one file has been copied it will then increment to the size of the next file to be copied. I wanted it to work like <code>CopyFileEx</code> in Windows that progress bar continuously increment when copying (I cant use <code>CopyFileEx</code> because I wanted to have my own implementation).</p>