Fix datetime field as now it is a datetime object

tryton/gui/window/view_form/model/field.py

@@ -115,6 +115,13 @@ class SelectionField(CharField):
     pass
 
 
+class DateTimeField(CharField):
+
+    def get_client(self, model):
+        value = super(DateTimeField, self).get_client(model)
+        return value and str(value) or False
+
+
 class FloatField(CharField):
 
     def validate(self, model):
@@ -380,4 +387,5 @@ TYPES = {
     'reference' : ReferenceField,
     'selection': SelectionField,
     'boolean': IntegerField,
+    'datetime': DateTimeField,
 }

tryton/gui/window/view_form/view/form_gtk/calendar.py

@@ -198,7 +198,7 @@ class DateTime(WidgetInterface):
         super(DateTime, self).display(model, model_field)
         if not model_field:
             return self.show(False)
-        self.show(model_field.get(model))
+        self.show(model_field.get_client(model))
 
     def show(self, dt_val, timezone=True):
         if not dt_val: