C#

private Hashtable AllTextBoxes = new Hashtable();

        //constructor code

    AllTextBoxes.Add(0, textBox1);
    AllTextBoxes.Add(1, textBox2);
                //...
                //You could make it more dynamic with a foreach(Control c in this.Controls), than cast c as Textbox. ...
}

        //button click
private void button2_Click(object sender, System.EventArgs e)
{
    OpenFileDialog dlg = new OpenFileDialog();
                dlg.Multiline = true;
    if (dlg.ShowDialog() == DialogResult.OK)
    {
        for(int x=0;x<AllTextBoxes.Count;x++)
        {
            TextBox actTB = AllTextBoxes[x] as TextBox;
            if(x<dlg.FileNames.Length)
            {
                actTB.Text = dlg.FileNames[x]; //add text
            }
            else
            {
                actTB.Text = ""; //clear text
            }
        }
    }
}

foreach(Control c in this.Controls)
{
    Label actlabel = c as Label;
    if(actlabel != null)
    {
	actlabel.Clear();
    }
    else
    {
        ListBox actlistbox = c as ListBox;
        if(actlistbox != null)
            actlistbox.Items.Clear();
    }
}

while(_running)<br />
{DoStuff();}<br />
else<br />
{<br />
  ReleaseExpensiveResources();<br />
 Thread.Sleep(Timeout.Infinite);<br />
}