The below example fetches the Productname and Productid from table and fill it into the Listbox
private void bindListBox()
{
string connString="Fetch connection string";
string sql = "SELECT Productid,Productname FROM Employees";
using (SqlCommand cmd = new SqlCommand(sql, new SqlConnection(connString)))
{
cmd.Connection.Open();
SqlDataReader rdr = cmd.ExecuteReader();
if (rdr.HasRows)
{
while (rdr.Read())
{
ListItem li = new ListItem(Convert.ToString(rdr["ProductName"]),
Convert.ToString(rdr["Productid"]));
ListBox1.Items.Add(li);
}
}
}
}