Hey @Siddharth Vyas ,
please follow below step
1. add container and dropdown inside container above table
2.create local variable named as categoryid(category identifier) and assign to dropdown variable property

3.add aggregate to dropdown list and create onchange action

4.when click on dropdown and changed value then dropdown action will get called and action contains refresh of aggregate which bind to table

5.add filter to GetInventories aggreagate as
Inventory.CategoryId=NullIdentifier() or Inventory.CategoryId=CategoryId
hope this will help you.
Thanks
Yogesh