ItemClass Seclector

I’m trying to figure out why I can’t search for an Item Class.  I’m saving the ItemClassID to SQL even though the ItemClassCD is shown which is what I want.  However, my search is always throwing a “failed to convert parameter vale from a String to an Int32” popup box.

Question: is there something that I’m missing to get my search to work?

Here’s my DAC code:

        [PXDBInt]
        [PXUIField(DisplayName = "Item Class")]     [PXSelector(typeof(SearchFor<INItemClass.itemClassID>.Where<INItemClass.itemClassCD.IsNotEqual<Empty>>), SubstituteKey = typeof(INItemClass.itemClassCD), DescriptionField = typeof(INItemClass.itemClassID))]
        public virtual int? ItemClassID { get; set; }
        [SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "DAC field BQL class uses same name with different case")]
        public abstract class itemClassID : BqlInt.Field<itemClassID> { }

Here’s my Grid:

    <px:PXGrid ID="grid" runat="server" DataSourceID="ds" Width="100%" Height="150px" 
AllowPaging="True" AllowSearch="true" AdjustPageSize="Auto" 
SkinID="Primary" AllowAutoHide="false" SyncPosition="true" MatrixMode="true">
        <Levels>
            <px:PXGridLevel DataMember="Records">
                <RowTemplate>
                    <px:PXSelector ID="edItemClass" runat="server" DataField="ItemClassID" AutoRefresh="True"></px:PXSelector>
                </RowTemplate>
                <Columns>
                <px:PXGridColumn DataField="ItemClassID" Width="70" ></px:PXGridColumn>
                    <px:PXGridColumn DataField="PrintPriceOnLabel" Type="CheckBox"></px:PXGridColumn>
                    <px:PXGridColumn DataField="LabelsPerUnit" CommitChanges="true"></px:PXGridColumn></Columns>
            
                <Mode AllowUpdate="True" AllowAddNew="True" ></Mode>
</px:PXGridLevel>
        </Levels>
        <AutoSize Container="Window" Enabled="True" MinHeight="150" />
        <Mode AllowAddNew="true" />
        <ActionBar >
    <Actions>
        <AddNew Enabled="true" />
    </Actions>
        </ActionBar>
    </px:PXGrid>