How to extract specific information from the selected item in a JComboBox?

Question

I have a form that has a ComboBox which it gets its items from a database. The combobox takes numerous column-items from a table inside the database. I want to take only one of these items (from the combobox) and copy it to a JTextField.

Here's the code of the creation of the ComboBox in the Order.java file:

cbinv = new JComboBox<>();
cbinv.setModel(new InvComboModel(con));

and the code from the InvComboModel.java:

public InvComboModel(Connection con) {
        try {
            stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                    ResultSet.CONCUR_UPDATABLE);
            String query = "SELECT * FROM inventory";
            rs = stmt.executeQuery(query);
        } catch (SQLException e) {
            System.out.println("InvComboModel: " + e.getMessage());
        }
    }

    @Override
    public String getElementAt(int index) {
        String lstn = null;
        try {
            rs.absolute(index + 1);
            lstn = rs.getString("category") + ", " + rs.getString("description") + ", "
                    + rs.getInt("price") + ", " + rs.getInt("quantity");
        } catch (SQLException e) {
            System.out.println("getElementAt(): " + e.getMessage());
        }
        return lstn;
    }
    
    @Override
    public int getSize() {
        int cnt = 0;
        try {
            rs.last();
            cnt = rs.getRow();
        } catch (SQLException ex) {
            System.out.println("getSize(): " + ex.getMessage());
        }
        return cnt;
    }

    public int getIdInvAt(int index) {
        int idInv = 0;
        try {
            rs.absolute(index + 1);
            idInv = rs.getInt("idinv");
        } catch (SQLException e) {
            System.out.println("getElementAt(): " + e.getMessage());
        }
        return idInv;
    }

So, I want when I select something on the Inventory Item to take the third value (which in this case is 500, example image) and copy it to the JTextField of the ItemPrice.

[example][1]: https://i.stack.imgur.com/BWQVw.jpg

In the Order.java file I have the following command but it copies all the selected item in the combobox:

tip.setText((String) cbinv.getSelectedItem());

and when I use the following command it takes the whole line again. It seems that I can't use any other method from the InvComboModel.java file

tip.setText((String) cbinv.getModel().getElementAt());

Thanks in advance.