Zip multiple files

[JustRonald]

Hi, I created an application which will zip .txt files into .zip For each textfile I selected in my listbox it creates one zip file. But I want to modify it now so all files I select would come in one zip file. This is a part of my form.cs file:

public Form1()
{
InitializeComponent();
listBox1.SelectionMode = SelectionMode.MultiExtended;
listBox1.DataSource = ClassFile.GetFiles(@"C:\");
}

private void button1_Click(object sender, EventArgs e)
{
/* Declaratie */
ArrayList bestanden;
string StoragePath;
string OldFile;
string NewFile;
string[] split;
int i;

/\* Initialisatie \*/
bestanden = new ArrayList();
StoragePath = @"C:\\";


/\* Code \*/
for (i = 0; i < listBox1.SelectedItems.Count; i++)
{
     split = listBox1.SelectedItems\[i\].ToString().Split('.');
     bestanden.Add(split\[0\]);
}            
     
listBox2.Items.Clear();

foreach (string bestand in bestanden)
{
     OldFile = StoragePath + bestand + ".txt";
     NewFile = StoragePath + bestand + ".zip";

     listBox2.Items.Add("Tekst bestand: " + OldFile);

     ClassFile.FileToZip(StoragePath, OldFile, NewFile);

     if (ClassFile.Overschijven == true)
     {
          listBox2.Items.Add("ZIP conversie succesvol: " + NewFile);
     }
     else
     {
          listBox2.Items.Add("ZIP conversie mislukt: " + OldFile);
     }
}

}

This is my class file:

public ArrayList GetFiles(string dir)
{
/* Declaratie */
ArrayList list;
DirectoryInfo di;
FileInfo[] rgFiles;

        /\* Initialisatie \*/
        list = new ArrayList();
        di = new DirectoryInfo(dir);
        rgFiles = di.GetFiles("\*.txt");

        /\* Code \*/
        foreach(FileInfo fi in rgFiles)
        {
            list.Add(fi.Name);          
        }
        return list;
    }

    public void FileToZip(string zipFileStoragePath, string fileToCompress, string zipFileName)
    {
        // Controle of het bestand wel bestaat
        if (File.Exists(fileToCompress) == false)
        {
            MessageBox.Show("Bestand niet gevonden.", "Fout", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
        else
        {
            // Controle of het zip bestand al bestaat
            if (File.Exist