GridView problem under not ispostback

we need code... actually you dont need to put data in session, it should be already in viewstate, no need to bind again...

yes we need code, however,  

If Not IsPostBack Then
End If

means if the page is not trigger the postback, and if you put this statement in page_load, after you click the EDIT button, since the EDIT button will trigger the postback, therefore every code inside of this IF statement will not run

markup
<asp:GridView ID="testGridView" runat="server" AutoGenerateColumns="False"
            EnableViewState="False">
            <Columns>
                <asp:BoundField DataField="gvOrderID" HeaderText="OrderID" ReadOnly="True"/>
                <asp:TemplateField HeaderText="ProductName">
                    <ItemTemplate>
                        <asp:Label id="labelProductName" runat="server" text='<%# Bind("gvProductName") %>'>></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:DropDownList id="ddlProductName" runat="server"
                             DataTextField="ProductName" DataValueField="ID" DataSource="<%# loadProducts %>" />                            
                       
                    </EditItemTemplate>                    
                </asp:TemplateField>                
                <asp:BoundField DataField="gvUnitPrice" HeaderText="UnitPrice" ReadOnly="True" SortExpression="UnitPrice" />
                <asp:BoundField DataField="gvQuantity" HeaderText="Quantity" ReadOnly="true" SortExpression="Quantity" />    
                <asp:TemplateField HeaderText="Action">
                    <ItemTemplate>
                        <asp:Button id="btnEdit" runat="server" Text="Edit" CommandName="Edit" />
                        <asp:Button id="btnDelete" runat="server" Text="Deate" CommandName="Delete" />
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:Button id="btnUpdate" runat="server" Text="Update" CommandName="Update"/>
                        <asp:Button id="btnCancel" runat="server" Text="Cancel" CommandName="Cancel" CausesValidation="false" />
                    </EditItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>


    Protected Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles form1.Load

        If Not IsPostBack Then
            loadProducts()
            loadOrderGridData
        End If

    End Sub
Private Sub loadOrderGridData()

        Dim NewRow As DataRow
        Dim table As DataTable = New DataTable("OrderDetail")
       
        Dim colItemOrderID As DataColumn = New DataColumn("gvOrderID", Type.GetType("System.String"))
        Dim colItemProductID As DataColumn = New DataColumn("gvProductID", Type.GetType("System.String"))
        Dim colItemProductName As DataColumn = New DataColumn("gvProductName", Type.GetType("System.String"))
        Dim colItemUnitPrice As DataColumn = New DataColumn("gvUnitPrice", Type.GetType("System.String"))
        Dim colItemQty As DataColumn = New DataColumn("gvQuantity", Type.GetType("System.String"))

        table.Columns.Add(colItemOrderID)
        table.Columns.Add(colItemProductID)
        table.Columns.Add(colItemProductName)
        table.Columns.Add(colItemUnitPrice)
        table.Columns.Add(colItemQty)

        ordDetailList = objOrderMapper.getOrder()

        For i = 0 To ordDetailList.Count - 1

            NewRow = table.NewRow()

            NewRow("gvOrderID") = CType(ordDetailList.Item(i), Order).OrderID  'testGridView.Rows(i).Cells(0).Text
            'gvLabelProduct = DirectCast(DirectCast(sender, GridView).Rows(i).FindControl("ddlProductName"), Label)
            NewRow("gvProductName") = CType(ordDetailList.Item(i), Order).ProductName 'gvLabelProduct.Text
            NewRow("gvUnitPrice") = CType(ordDetailList.Item(i), Order).Quantity  'testGridView.Rows(i).Cells(2).Text
            NewRow("gvQuantity") = CType(ordDetailList.Item(i), Order).UnitPrice  'testGridView.Rows(i).Cells(3).Text

            table.Rows.Add(NewRow)

        Next

        'Dim dvData As DataView = New DataView(table)
        Session("OrderTable") = table
       
        BindData()


    End Sub


    Private Sub BindData()
        Me.testGridView.DataSource = Session("OrderTable")
        Me.testGridView.DataBind()
    End Sub

 Function loadProducts() As IList
        prdList = objOrderMapper.getProducts()
        Return prdList
    End Function

what is this doing? loadProducts is a function and used like a sub...

   Function loadProducts() As IList
        prdList = objOrderMapper.getProducts()
        Return prdList
    End Function

    Protected Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles form1.Load
        If Not IsPostBack Then
            loadProducts() >>>>>>>>>>> ????? <<<<<<<<<<<
        End If
    End Sub

;) got it, you can remove this line

and also why it is form1_Load, should not it be Page_Load?

    Protected Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles form1.Load
        If Not IsPostBack Then
            loadOrderGridData()
        End If
    End Sub

Select allOpen in new window

maybe you turned off your viewstate... thats why you get nothing...

do you have anything like this

EnableViewState="false"

in page/form or web config?