Question

I have a ListBox which I put some files, if the file is not AVI I automatically converts it but I want when the files converting message will write on a label that the files are now converted to another format, i know i need use Dispatcher in order to update the UI thread but i use now Winform instead of WPF, and i need help with this.
BTW i cannot use Task because i am using .Net 3.5

private void btnAdd_Click(object sender, EventArgs e)
{
    System.IO.Stream myStream;
    OpenFileDialog thisDialog = new OpenFileDialog();
    thisDialog.InitialDirectory = "c:\\";
    thisDialog.Filter = "All files (*.*)|*.*";
    thisDialog.FilterIndex = 1;
    thisDialog.RestoreDirectory = false;
    thisDialog.Multiselect = true; // Allow the user to select multiple files
    thisDialog.Title = "Please Select Source File";
    thisDialog.FileName = lastPath;
    List<string> list = new List<string>();

    if (thisDialog.ShowDialog() == DialogResult.OK)
    {
        foreach (String file in thisDialog.FileNames)
        {
            try
            {
                if ((myStream = thisDialog.OpenFile()) != null)
                {
                    using (myStream)
                    {
                        listBoxFiles.Items.Add(file);
                        lastPath = file;
                    }
                }
            }

            catch (Exception ex)
            {
                MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
            }
        }

        for (int i = 0; i < listBoxFiles.Items.Count; i++)
        {
            string path = (string)listBoxFiles.Items[i];
            FileInfo fileInfo = new FileInfo(path);

            if (fileInfo.Extension != ".AVI")
            {
                listToRemove.Add(path);
            }
        }

        (new System.Threading.Thread(sendFilesToConvertToPcap)).Start();

        foreach (string file in listToRemove) //remove all non .AVI files from listbox
        {
            listBoxFiles.Items.Remove(file);
        }
    }
}

this function need to change the Label:

        public void sendFilesToConvertToPcap()
        {
            if (listToRemove.Count == 0) // nothing to do
            {
                return;
            }

lblStatus2.Content = "Convert file to .AVI...";

            foreach (String file in listToRemove)
            {
                FileInfo fileInfo = new FileInfo(file);
                myClass = new (class who convert the files)(fileInfo);
                String newFileName = myClass.mNewFileName;
                listBoxFiles.Items.Add(myClass._newFileName);
            }

lblStatus2.Content = "Finished...";

        }

Answer 1

public void sendFilesToConvertToPcap()
{
   .....
   ....
   this.Invoke((MethodInvoker)delegate {
   lblStatus2.Text = "Convert file to .AVI..."; });

 ....
}