private void textBox1_TextChanged(object sender, EventArgs e)
{
if (textBox1.Text != "")
{
dataGridView1.DataSource = db.Load_Purchase_Order().
Where(o => o.PO_Number.Contains(textBox1.Text.ToUpper())).ToList();
if (dataGridView1.RowCount == 0)
{
MessageBox.Show("No results found");
textBox1.Clear();
dataGridView1.DataSource = db.Load_Purchase_Order_1().ToList();
}
}
dataGridView1.DataSource = db.Load_Purchase_Order_1().ToList();
}