Make relationchoice field works (Plone 5)

src/collective/z3cform/datagridfield/__init__.py

@@ -6,6 +6,7 @@
 from .interfaces import IDataGridField  # noqa # pylint: disable=unused-import
 from .interfaces import IRow  # noqa # pylint: disable=unused-import
 from .row import DictRow  # noqa # pylint: disable=unused-import
+from .row import RowList  # noqa # pylint: disable=unused-import
 from zope.i18nmessageid import MessageFactory
 
 

src/collective/z3cform/datagridfield/configure.zcml

@@ -45,6 +45,7 @@
   <adapter factory=".datagridfield.GridDataConverter" />
   <adapter factory=".datagridfield.DataGridFieldSubformAdapter" />
   <adapter factory=".datagridfield.DataGridValidator" />
+  <adapter factory=".row.RowDataManager" />
   <adapter
       factory=".converters.DictRowSerializer"
       zcml:condition="installed transmogrify.dexterity"

src/collective/z3cform/datagridfield/datagridfield.py

@@ -364,7 +364,10 @@ class DataGridFieldObjectSubForm(AutoExtensibleSubForm):
     """
     def __init__(self, context, request, parentWidget):
         # copied from z3c.form 3.2.10
-        self.context = context
+        if context:
+            self.context = context
+        else:
+            self.context = parentWidget.form.context
         self.request = request
         self.__parent__ = parentWidget
         self.parentForm = parentWidget.form
@@ -427,6 +430,9 @@ def updateWidgets(self):
                 self.widgets,
                 self.__parent__.__parent__
             )
+        #Add context to field widgets in sub form
+        for widget in self.widgets.values():
+            widget.context = self.context
         return rv
 
     def setupFields(self):

src/collective/z3cform/datagridfield/interfaces.py

@@ -2,6 +2,7 @@
 
 from z3c.form.interfaces import IMultiWidget
 from plone.app.z3cform.interfaces import IPloneFormLayer
+from zope.schema.interfaces import IList
 from zope.schema.interfaces import IObject
 from zope.schema.interfaces import ValidationError
 
@@ -29,3 +30,8 @@ def __init__(self, fieldname, schema):
 class IRow(IObject):
     """A row. The schema defines dict keys.
     """
+
+
+class IRowList(IList):
+    """A List schema field contain the row.
+    """

src/collective/z3cform/datagridfield/overrides.zcml

@@ -0,0 +1,16 @@
+<configure
+    xmlns="http://namespaces.zope.org/zope"
+    xmlns:browser="http://namespaces.zope.org/browser"
+    xmlns:zcml="http://namespaces.zope.org/zcml"
+    >
+
+  <configure zcml:condition="have plone-5">
+    <browser:page
+        name="getSource"
+        for="z3c.form.interfaces.IWidget"
+        class=".patch.SourceView"
+        permission="zope.Public"
+        />
+  </configure>
+
+</configure>

src/collective/z3cform/datagridfield/patch.py

@@ -0,0 +1,19 @@
+from plone.app.content.browser.vocabulary import SourceView
+
+
+class SourceView(SourceView):
+    """ Patch Plone SourceView's get_context() method 
+        since context of the subform is a dictionary (which is correct)
+    """
+
+    def get_context(self):
+        #Get form object
+        form = self.context.form
+        try:
+            parent_form = form.__parent__.form
+        except:
+            parent_form = None
+        if parent_form:
+            return parent_form.context
+        else:
+            return form.context

src/collective/z3cform/datagridfield/row.py

@@ -4,11 +4,18 @@
 """
 from interfaces import AttributeNotFoundError
 from interfaces import IRow
+from interfaces import IRowList
 from z3c.form.interfaces import NO_VALUE
+from z3c.form.interfaces import IDataManager
+from z3c.form.datamanager import AttributeField
+from zope.interface import Interface
 from zope.interface import implementer
+from zope.component import adapter
+from zope.component import getMultiAdapter
 from zope.schema import Field
 from zope.schema import getFields
 from zope.schema import Object
+from zope.schema import List
 from zope.schema.interfaces import IChoice
 from zope.schema.interfaces import WrongContainedType
 
@@ -57,3 +64,49 @@ def _validate(self, value):
     def set(self, object, value):
         # Override Object field logic
         Field.set(self, object, value)
+
+
+@implementer(IRowList)
+class RowList(List):
+    __doc__ = IRowList.__doc__
+
+
+@adapter(Interface, IRowList)
+class RowDataManager(AttributeField):
+    """Proxy to call datamanager for each field in the subform."""
+
+    @property
+    def subfields(self):
+        return getFields(self.field.value_type.schema)
+
+    def get(self):
+        """Gets the target"""
+        raw_value = []
+        # Calling query() here will lead to infinite recursion!
+        try:
+            raw_value = super(RowDataManager, self).get()
+        except AttributeError:
+            raw_value = None
+        if not raw_value:
+            return []
+
+        resolved_value = []
+        for item in raw_value:
+            new_item = {}
+            for name, field in self.subfields.items():
+                dm = getMultiAdapter((item, field), IDataManager)
+                new_item[name] = dm.get()
+            resolved_value.append(new_item)
+        return resolved_value
+
+    def set(self, value):
+        """Sets the relationship target"""
+        value = value or []
+        new_value = []
+        for item in value:
+            new_item = {}
+            for name, field in self.subfields.items():
+                dm = getMultiAdapter((new_item, field), IDataManager)
+                dm.set(item[name])
+            new_value.append(new_item)
+        super(RowDataManager, self).set(new_value)