if (connection.State == ConnectionState.Closed)
                    connection.Open();
                
                command = new SqlCommand();
                command.CommandText = "sp_Get_ControlValues";
                command.CommandType = CommandType.StoredProcedure;
                command.Connection = connection;
                command.Parameters.AddWithValue("@uid", uid);
                SqlDataAdapter daPack = new SqlDataAdapter(command);
                DataSet dsPack = new DataSet();
                daPack.Fill(dsPack);
                //ddlPackPeriod.DataSource = dsPack;
                //ddlPackName.DataSource = dsPack;
                //ddlPackPeriod.DataTextField = "PackagePeriod";
                //ddlPackName.DataTextField = "PackageName";
                txtOldExpDate.Text = dsPack.Tables[0].Rows[0]["OldExpiryDate"].ToString();
                txtNoOfExtConn.Text = dsPack.Tables[0].Rows[0]["NoOfExtraConn"].ToString();
                txtAmntToPay.Text = dsPack.Tables[0].Rows[0]["Balance"].ToString();
                ddlPackPeriod.DataBind();
                ddlPackName.DataBind();
 
In 'pageload'  iam alredy binded those two dropdowns and those dropdowns are cascading
 
so when I click on 'Suearch' button I just want to show as selected  of  'UserId' col values
so How?