loading data in gridview is slow - asp.net

Question

For having the result like below and showing column 2 (user control) & column 3 (user control) grouped by column 1. I have made the code like below but it is slow , actually when I use just column 1 , loading is quick (5 seconds) , when I use column 1 & column2 (user control "document list") loading is 10 seconds, and when I use column 1 & column 2 (document list") & column3 ("DocTransList") loading is 45 seconds. I think my code in LINQ is not efficient , but I do not know how to solve it.
TRANSMITTAL No Documents REV
TT-001 DOC-001 01
DOC-002 01
public partial class Transmittals : System.Web.UI.Page
{
class TransmittalPresentationModel
{
public int TransID { get; set; }
public String TransmittalNo { get; set; }
public IEnumerable<tblDocument> Documents { get; set; }
public IEnumerable<tblTransmittall> DocTrans { get; set; }
}
private EDMSDataContext _DataContext;
protected void Page_Load(object sender, EventArgs e)
{
_DataContext = new EDMSDataContext();
if (!IsPostBack)
{
DisplayAuthors();
}
}
private void DisplayAuthors()
{
var query =
from transmittal in _DataContext.tbltransmittalNos
orderby transmittal.TRANSMITTAL
select new TransmittalPresentationModel
{
TransID = transmittal.TransID,
TransmittalNo = transmittal.TRANSMITTAL,
Documents = transmittal.tblTransmittalls.Select(Transmittals => Transmittals.tblDocument),
DocTrans = transmittal.tblTransmittalls
};
GridViewTransmittals.DataSource = query.ToList();
GridViewTransmittals.DataBind();
}
protected void GridViewTransmittals_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.DataItem == null) return;
TransmittalPresentationModel transmittal = (TransmittalPresentationModel)e.Row.DataItem;
DocumentList documentList = (DocumentList)e.Row.FindControl("DocumentList1");
DocTransList doctranslist = (DocTransList)e.Row.FindControl("DocTransList2");
documentList.Documents = transmittal.Documents;
documentList.DataBind();
doctranslist.DocTrans = transmittal.DocTrans;
doctranslist.DataBind();
}
}

Answer 1

Your having issues because your records all need to load into the GridView on each page load / refresh. This pulls from the database and draws each row each time which is time consuming.
Better options are to use Ajax to load your GridView.
Or use Paging on the server side and only give the data to your page it needs.