C#

//Show the listbox
private void button1_Click(object sender, System.EventArgs e)
{
	this.listBox1.Visible = true;
}

// hide the listbox if it looses focus
private void listBox1_Leave(object sender, System.EventArgs e)
{
	this.listBox1.Visible = false;
}

//event handler for Form.MouseDown (and later for each control)
private void Control_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
	if(sender != this.listBox1)
		this.listBox1.Visible=false;
}

protected override void OnControlAdded(ControlEventArgs e)
{
	e.Control.MouseDown += new MouseEventHandler(Control_MouseDown);
	base.OnControlAdded (e);
}

//'values' is the name of the array of short values
byte[] buffer=new byte[values.Length*2];
Buffer.BlockCopy(values,0,buffer,0,buffer.Length);
//'buffer' now holds the short values as bytes