C# listbox updating
===

i'm trying to update this Listbox in C#. this is my first program in C#, not exactly sure how things work. 

    public partial class progHider : Form
    {
        String[] processList;

        public progHider()
        {
            InitializeComponent();
        }

        private void progHider_Load(object sender, EventArgs e)
        {
            List.Items.AddRange(getList());
        }

        private String[] getList()
        {
            Process[] processlist = Process.GetProcesses();
            processList = new String[Process.GetProcesses().Length];
            int index = 0;
            foreach (Process process in processlist)
            {
                if (!String.IsNullOrEmpty(process.MainWindowTitle))
                {
                    processList[index] = process.MainWindowTitle;
                    index++;
                }
            }

            return processList;
        }

        private void btnrefresh_Click(object sender, EventArgs e)
        {
            List.DataSource = null;
            this.Update();
        }
    
One question is how do I update Listbox? I can't figure out how to accomplish it. am I even doing this right?
Another question is how does private void progHider_Load(object sender, EventArgs e) work? is it only used once? can you call it?
