how to retrieve data from a session table

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:

Code:

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                PBProductID.DataSource = Session("TableProductAll")
                PBProductID.DataBind()

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Session("TableProductAll") is filled when user first login to the system in the login page
On PBProductID_SelectedIndexChanged event:

Code:

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  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

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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.

1. Turn Option Strict ON and fix any errors resulted from this.

2. You should load the product table once on 1st page load and don't load it again for sub-sequencen page loads. To control this, you test the Page.IsPostBack property

Code:

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If Not Page.IsPostBack Then
  'Load you product table data here
  '
  'Then save that to a session variable
  Session("TableProductAll") = theProductTable
End If
'Now bind that productTable to your control
Dim productTable as DataTable = DirectCast(Session("TableProductAll"), DataTable)
PBProductID.DataSource = productTable
PBProductID.DataBind()

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On PBProductID_SelectedIndexChanged event:

Code:

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  Dim strCriteria As String = ""
  PBSalesPrice.Text = 0
  strCriteria = " ProductID = '" & PBProductID.Text & "'"
  Dim productTable As DataTable = DirectCast(Session("TableProductAll"), DataTable)
  Dim SearchRow As DataRow() = productTable.Select(strCriteria)
  If SearchRow.Count > 0 Then PBSalesPrice.Text = SearchRow(0)("pPriceSales").ToString

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