No value given for one or more required parameters

I get this error with this code?
<asp:SqlDataSource ID="SqlGridview" runat="server" ConnectionString="<%$ ConnectionStrings:Inventory %>" ProviderName="<%$ ConnectionStrings:Inventory.ProviderName %>" SelectCommand="SELECT [Item_Name], [Item_Model], Item_Name + ' ' + Item_Model as FullItem, [Item_Quantity], [MDDT], [MDTM], MDDT+MDTM as Fullname, [Edited_by], [Comments] FROM [Inventory_History] WHERE ([Item_Name] = ? and [Item_Model] = ?) ORDER BY Fullname DESC"> <SelectParameters> <asp:ControlParameter ControlID="ddlInventoryList" Name="Item_Name" PropertyName="SelectedValue" Type="String" /> </SelectParameters> </asp:SqlDataSource>