C#

protected override void WndProc(ref Message m)
        {
            if ((m.Msg == WM_DEVICECHANGE) && (m.WParam == DBT_DEVICEARRIVAL))
            {
                int deviceType = Marshal.ReadInt32(m.LParam, sizeof(int));


                if (deviceType == LOGICAL_VOLUME)
                {
                    uint unitMask = (uint)Marshal.ReadInt32(m.LParam, sizeof(int) * 3);


                    if (unitMask != 0)
                    {
                        char driveLetter = DriveLetterFromUnitMask(unitMask);
                        // some more code here but irrelevant.
                        backgroundWorker1.RunWorkerAsync(copy);
                        // the copy is a new object class containing data, however it is irrelevant
                    }
                }
             }
         }

public void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            CopyObject a = e.Argument as CopyObject;
            RecursiveCopy.FullCopy(a.sConfigLocation, a.sourceFolder, a.destFolder, a.sDriveName, a.iniFile);
            e.Result = "1";
        }
     public void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {  
            string message = e.UserState as string;
            fileCopyingLbl.Text = message; // Update the label control.
        }

public class RecursiveCopy
    {
        public static void FullCopy(string sConfigLocation, string sourceFolder, string destFolder, string sDriveName, object iniFile)
        {
            if (!Directory.Exists(destFolder))
                Directory.CreateDirectory(destFolder);
  
            int countFile = 0;
            string[] files = Directory.GetFiles(sourceFolder);
            foreach (string file in files)
            {
                string name = Path.GetFileName(file);
                string dest = Path.Combine(destFolder, name);
                DateTime WriteTime = File.GetLastWriteTime(dest);
                IniFunctions.WriteToIni(sConfigLocation, sDriveName, file, WriteTime.ToString(), iniFile);
                object fileCopying1 = file;
                PenDriveBackup myClass = new PenDriveBackup();
                myClass.backgroundWorker1.ReportProgress(0, file); // This will call backgroundWorker1_ProgressChanged method in the main class.
                                                                   //  If I were to put a MessageBox.Show(message); into the ProgressChanged method
                                                                   //  then I can see the correct files changing however the label does not get updated.
                                                                   //  I'm not sure what the problem is but I'm guessing it's something to do with the
                                                                   //  PenDriveBackup myClass = new PenDriveBackup(); not taking control of the form?
                File.Copy(file, dest, true);
            }
            string[] folders = Directory.GetDirectories(sourceFolder);
            foreach (string folder in folders)
            {
                string name = Path.GetFileName(folder);
                string dest = Path.Combine(destFolder, name);
                Console.WriteLine("Copying " + folder);
                FullCopy(sConfigLocation, folder, dest, sDriveName, iniFile);
            }
        }
     }

<br />
using System;<br />
using System.Collections.Generic;<br />
using System.ComponentModel;<br />
using System.Data;<br />
using System.Drawing;<br />
using System.Linq;<br />
using System.Text;<br />
using System.Windows.Forms;<br />
<br />
namespace _19_richtextbox<br />
{<br />
    public partial class Form1 : Form<br />
    {<br />
        public Form1()<br />
        {<br />
            InitializeComponent();<br />
        }<br />
<br />
        private void richTextBoxHome_KeyDown(object sender, KeyEventArgs e)<br />
        {<br />
            if (e.KeyValue == (char)(Keys.Return))<br />
            {<br />
                richTextBoxChat.AppendText("Home:" + richTextBoxHome.Text + "\n");<br />
                richTextBoxHome.Clear();<br />
            }<br />
        }<br />
<br />
    }<br />
}<br />