Q&A: How can I get a component to manipulate its parent's inventory

From DANSE

The simple answer is: bettter not to. Ask a component to manipulate it's parent's inventory is dangerous. That means you are somehow overriding the user inputs of parent's properties by the user inputs of a child's properties. Users of this kind of program will be confused by unexpected results due to overriding of user inputs.

If a component wants to know what is going on in its parent, you can pass a reference of the parent to the child somehow. But it usually means a bad design of the parent-child relationship.