How do I open the connection one time not two time

string str1 = "select eq_type_name + '-'+ eq_type_name_arabic as txtField,eq_type_no from equit_type;";
               string str2 = "SELECT ID, name FROM MendCompany";
               OleDbConnection conn = new OleDbConnection(cc);
               OleDbCommand cmd = new OleDbCommand(str1, conn);
               conn.Open();

               Dr_device.DataSource = cmd.ExecuteReader();
               Dr_device.DataTextField = "txtField";
               Dr_device.DataValueField = "eq_type_no";
               Dr_device.DataBind();
               conn.Close();
               conn.Open();
               cmd.CommandText = str2;
               Dr_kind0.DataSource = cmd.ExecuteReader();
               Dr_kind0.DataTextField = "name";
               Dr_kind0.DataValueField = "ID";
               Dr_kind0.DataBind();
               conn.Close();
               Dr_device.Items.Insert(0, " اختر الجهاز");
               Dr_kind0.Items.Insert(0, "**اختر شركة الإصلاح**");