Grid Records not updated dynamically

Hi everyone,
I’m new to Acumatica, i made a custom processing form, the grid of this from contains soLines fetched using this code:
 

 public PXFilteredProcessingJoin<SOLine, SOFilter,
            InnerJoin<InventoryItem, On<SOLine.inventoryID, Equal<InventoryItem.inventoryID>>,
            Where<Current<SOFilter.orderType>, IsNull,
                                Or<SOLine.orderType, Equal<Current<SOFilter.orderType>>>>,
                            And<Where<Current<SOFilter.inventoryItem>, IsNull,
                                Or<SOLine.inventoryID, Equal<Current<SOFilter.inventoryItem>>> 
                SOLineFiltered;

I set the DataMember for the grid to SOLineFiltered, and the records were fetched successfully.

the problem is that the filter fields are not working, when i choose IN for example as ordertype and 11111 as inventoryID the grid is not updated.

can anyone help me on this?