How to retrieve data from a session table

Question

I developing an invoice page where user will select Product from a combo box (approx. 500 + item). I am loading product Name, Product ID, sales price in a session Table. After selecting the product, a textbox value will Sales Price. But it is taking so much time.
On page load event:
                 PBProductID.DataSource = Session("TableProductAll")
  PBProductID.DataBind()
Session("TableProductAll") is filled when user first login to the system in the login page
On PBProductID_SelectedIndexChanged event:
Dim strCriteria As String = ""
PBSalesPrice.Text = 0
strCriteria = " ProductID = '" & PBProductID.Text & "'"
Dim SearchRow As DataRow() = Session("TableProductAll").Select(strCriteria)
If SearchRow.Count > 0 Then PBSalesPrice.Text = SearchRow(0)("pPriceSales").ToString
How to reduce the time at PBProductID_SelectedIndexChanged event (at present it taking apprx. 45 sec or more) 
 Looking for a better solution of way to fill a combo box and retrieve sales price from that table after selecting the product ID.