ListView not updating

Hi,

I have the following code:

    <table>
        <asp:ListView   ID="ltvOrderDetails"
                        runat="server"
                        DataSourceID="sqlDS_OrderDetails"
                        DataKeyNames="ItemInOrderID"
                        EnableModelValidation="True">
            <LayoutTemplate>
                <asp:PlaceHolder runat="server" ID="itemPlaceholder"></asp:PlaceHolder>
            </LayoutTemplate>
            <ItemTemplate>
                <tr runat="server">
                    <td style="text-align: left; width: 250px; padding-left: 10px;"><asp:Label ID="lblItemName" runat="server" Text='<%#Eval("ItemName") %>' CssClass="OrderItem" /></td>
                    <td style="text-align: right; width: 80px;"><asp:Label ID="lblUnitInterCount" runat="server" Text='<%#Eval("UnitInterCount") %>' CssClass="OrderItem" />&nbsp;<asp:Label ID="lblUnitText" runat="server" Text='<%#Eval("UnitText") %>' CssClass="OrderItem" /></td>
                    <td style="text-align: right; width: 70px;"><asp:Label ID="lblItemCount" runat="server" Text='<%#Eval("ItemCount") %>' CssClass="OrderItem" /></td>
                    <td style="text-align: right; width: 70px;"><asp:Label ID="lblPrice" runat="server" Text='<%#Eval("SellPrice") %>' CssClass="OrderItem" />&nbsp;<asp:Label ID="lblCurrency" runat="server" Text='<%#Eval("CurrencySymbol") %>' CssClass="OrderItem" /></td>
                    <td style="text-align: right; width: 70px;"><asp:Label ID="lblDphRate" runat="server" Text='<%#Eval("DphRate") %>' CssClass="OrderItem" /></td>
                    <td style="padding-left: 20px; padding-right: 10px;"><asp:Button ID="EditButton" runat="server" Text="Edit" CommandName="Edit" /><asp:HiddenField ID="hifItemInOrderID" runat="server" Value='<%#Eval("ItemInOrderID") %>' />
                    </td>
                </tr>
            </ItemTemplate>
            <EditItemTemplate>
                <tr><td colspan="6"><asp:HiddenField ID="hifItemInOrderID" runat="server" Value='<%#Eval("ItemInOrderID") %>' /></td></tr>
                <tr runat="server" style="background-color: #d0d0d0;">
                    <td style="text-align: left; width: 250px; padding-left: 10px;">
                        <asp:DropDownList ID="ddlItemName" runat="server" SelectedValue='<%#Bind("ItemID")%>' DataSourceID="sqlDS_Items" DataTextField="ItemName" DataValueField="ItemID" />
                        <asp:SqlDataSource ID="sqlDS_Items" runat="server" ConnectionString="<%$ ConnectionStrings:EStoreConnectionString %>" SelectCommand="Admin_Items_List" SelectCommandType="StoredProcedure"></asp:SqlDataSource>
                    </td>
                    <td style="text-align: right; width: 80px;">
                        <asp:DropDownList ID="ddlUnit" runat="server" DataSourceID="sqlDS_Units" DataTextField="UnitDisplay" DataValueField="UnitID" SelectedValue='<%#Bind("UnitID")%>' Width="75px" Font-Names="Trebuchet MS" Font-Size="Small" />
                        <asp:SqlDataSource ID="sqlDS_Units" runat="server" ConnectionString="<%$ ConnectionStrings:EStoreConnectionString %>" SelectCommand="Admin_Units" SelectCommandType="StoredProcedure"></asp:SqlDataSource>
                    </td>
                    <td style="text-align: right; width: 70px;"><asp:TextBox ID="txtItemCount" runat="server" Text='<%#Bind("ItemCount") %>' Width="40px" CssClass="Txt2Edit" /></td>
                    <td style="text-align: right; width: 70px;"><asp:TextBox ID="txtPrice" runat="server" Text='<%#Bind("SellPrice") %>' Width="40px" CssClass="Txt2Edit" />&nbsp;<asp:Label ID="lblCurrency" runat="server" Text='<%#Eval("CurrencySymbol") %>' CssClass="OrderItem" /></td>
                    <td style="text-align: right; width: 70px;"><asp:TextBox ID="txtDphRate" runat="server" Text='<%#Bind("DphRate") %>' Width="40px" CssClass="Txt2Edit" /></td>
                    <td style="padding-left: 20px; padding-right: 10px;"><asp:Button ID="UpdateButton" runat="server" Text="Update" CommandName="Update" /><asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" /></td>
                </tr>
            </EditItemTemplate>
        </asp:ListView>
    </table>

    <asp:SqlDataSource ID="sqlDS_OrderDetails"
                        runat="server"
                        ConnectionString="<%$ ConnectionStrings:EStoreConnectionString %>"
                        SelectCommand="Admin_OrderDetails" 
                        SelectCommandType="StoredProcedure" 
                        UpdateCommand="Admin_OrderDetails_Update"
                        UpdateCommandType="StoredProcedure">
        <SelectParameters>
            <asp:ControlParameter   ControlID="ddlOrders2Edit" 
                                    Name="OrderID" 
                                    PropertyName="SelectedValue" 
                                    Type="Int64" />
        </SelectParameters>
        <UpdateParameters>
            <asp:Parameter Name="ItemInOrderID" Type="Int64" />
            <asp:Parameter Name="ItemID" Type="Int64" />
            <asp:Parameter Name="ItemCount" Type="Int16" />
            <asp:Parameter Name="SellPrice" Type="Double" />
            <asp:Parameter Name="DphRate" Type="Double" />
            <asp:Parameter Name="UnitID" Type="Int16" />
        </UpdateParameters>
    </asp:SqlDataSource>

plus 2 procedures defined in SQL Server for Select and Update

UPDATE SQL PROCEDURE:

CREATE PROCEDURE [dbo].[Admin_OrderDetails_Update]

@ItemInOrderID	BIGINT,
@ItemID			BIGINT,
@ItemCount		SMALLINT,
@SellPrice			FLOAT,
@DphRate			FLOAT,
@UnitID			SMALLINT
	
AS

UPDATE		ItemsInOrder

SET			ItemID  = @ItemID, 
			ItemCount = @ItemCount,
			SellPrice = @SellPrice,
			DphRate = @DphRate,
			UnitID = @UnitID 
			
WHERE		ItemInOrderID  = @ItemInOrderID

My problem is that the db item is updated with NULL values instead of values from controls.

Any suggestions? Thanks!