line: disable column 'quantity_balance' if cashbook-feature != asset

line.py

@@ -58,9 +58,11 @@ class Line(SecondUomMixin, metaclass=PoolMeta):
         }, depends=['currency_digits', 'quantity_digits', 'feature']),
         'on_change_with_asset_rate')
     quantity_balance = fields.Function(fields.Numeric(string='Quantity',
-        digits=(16, Eval('quantity_digits', 4)),
+        digits=(16, Eval('quantity_digits', 4)), readonly=True,
         help='Number of shares in the cashbook up to the current row if the default sort applies.',
-        readonly=True, depends=['quantity_digits']),
+        states={
+            'invisible': Eval('feature', '') != 'asset',
+        }, depends=['quantity_digits', 'feature']),
         'on_change_with_quantity_balance')
 
     @classmethod
@@ -134,7 +136,7 @@ class Line(SecondUomMixin, metaclass=PoolMeta):
                     })
         return result
 
-    @fields.depends('id', 'date', 'cashbook', \
+    @fields.depends('id', 'date', 'cashbook', 'feature',\
         '_parent_cashbook.id', 'reconciliation', \
         '_parent_reconciliation.start_quantity',\
         '_parent_reconciliation.state')
@@ -142,10 +144,12 @@ class Line(SecondUomMixin, metaclass=PoolMeta):
         """ get quantity-balance
         """
         Line2 = Pool().get('cashbook.line')
-        return Line2.get_balance_of_line(self,
-            field_name='quantity',
-            credit_name='quantity_credit',
-            debit_name='quantity_debit')
+
+        if self.feature == 'asset':
+            return Line2.get_balance_of_line(self,
+                field_name='quantity',
+                credit_name='quantity_credit',
+                debit_name='quantity_debit')
 
     @fields.depends('quantity', 'amount', 'currency_digits', 'quantity_digits')
     def on_change_with_asset_rate(self, name=None):