我使用以下代码：

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<FileInfo> files = new List<FileInfo>();
      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 & 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();
    }
  }
}

复制文件并在进度条中显示状态时，将其张贴在此处（ nobugz
张贴在此处）。

我想在复制（尤其是大文件）时不断增加进度条的值。此示例代码中发生的是，进度条上的值在每个复制的文件上停止，并且在复制了一个文件之后，它将递增到下一个要复制的文件的大小。我希望它能像CopyFileEx在Windows中一样工作，在复制时进度条会不断增加（我无法使用，CopyFileEx因为我想拥有自己的实现）。