how Getting data from threads??

hi every one
i want to give data from database and bound to a grid from a thread i write this sample code:
**************************************
private void thr()
{
dataGridView1.DataSource = null;
linq1DataContext da = new linq1DataContext();
var p = from cust in da.Customers select cust;
dataGridView1.DataSource = p;
dataGridView1.Refresh();
}

private void sbButton1_Click(object sender, EventArgs e)
{

th = new Thread(new ThreadStart(thr));
th.IsBackground = true;
th.Start();
}
************************************************** **
and i use sqlserver2000 and northwide database
when i click the button and run thread the grid fills with data but after this the form don't respond
and the grides scrolls dont work.
everyone know how can i fix this problem.
thanks.