[IronPython] .NET attributes for methods
Shri Borde
Shri.Borde at microsoft.com
Fri Nov 13 16:33:04 CET 2009
I can help you create a property. And I can help you get it to work with your decorators (you can check if the "name" property exposes your @notify_property wrapper methods or not, and presumably that works). Beyond that, you are on your own :)
I would try calling the property methods to make sure they are accessible. Something like this. If that works, I am not sure what Silverlight needs to make databinding happy.
props = a.root.listbox1.Items[0].GetType().GetProperties()
prop = props[0]
prop.GetGetMethod.Invoke(a, None) # call using Reflection
About the "SystemError: Application code cannot access System.AppDomain.get_CurrentDomain() using Reflection." error when defining interfaces, it could be worked around. We need to call AppDomain.DefineDynamicAssembly, and IronPython itself does do this. So its just a question of figuring out the right way to access an AppDomain instance. Will look into it, but I doubt it will help you with data binding.
From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Lukas Cenovsky
Sent: Friday, November 13, 2009 5:42 AM
To: Discussion of IronPython
Subject: Re: [IronPython] .NET attributes for methods
This looks very promising but I cannot make it work. I have changed product.py in DevHawk's example to:
#from clrtypeold import ClrMetaclass
import clrtype
class Product(object):
#__metaclass__ = ClrMetaclass
__metaclass__ = clrtype.ClrClass
_clrnamespace = "DevHawk.IronPython.ClrTypeSeries"
#_clrproperties = {
#"name":str,
#"cost":float,
#"quantity":int,
#}
def __init__(self, name, cost, quantity):
self.name = name
self.cost = cost
self.quantity = quantity
def calc_total(self):
return self.cost * self.quantity
@property
@clrtype.accepts()
@clrtype.returns(str)
def name(self):
return self._name
@name.setter
@clrtype.accepts(str)
@clrtype.returns()
def name(self, value):
self._name = value
When I run it I don't see any items in the listbox. When I check the name, it is a property:
py> a.root.listbox1.Items[0]
=> <Product object at 0x000000000000002B>
py> a.root.listbox1.Items[0].GetType().GetProperties()
=> Array[PropertyInfo]((<System.Reflection.RuntimePropertyInfo object at 0x000000000000002C [System.String name]>))
Whe I used the old clrtype with _clrproperties = {'name': str, ...}, it worked.
--
-- Lukáš
Shri Borde wrote:
Here is an updated version of clrtype.py that uses @property + @clrtype.accepts/@clrtype.returns to indicate a CLR property, instead of using "_clrproperties". I think its more Pythonic in general, but also you should be able to modify @notify_property to work with it.
Note that notify_property won't just work. You will have to change it to propagate the func_name, arg_types, and return_type properties from the old getter/setter function objects to the new getter/setter function objects since these values are used by clrtype to generate the CLR members. Something like this:
class notify_property(property):
def propagate_attributes(old_function, new_function):
new_function.func_name = old_function.func_name
new_function.arg_types = old_function.arg_types
new_function.return_type = old_function.return_type
def __init__(self, getter):
def newgetter(slf):
try:
return getter(slf)
except AttributeError:
return None
propagate_attributes(getter, newgetter)
super(notify_property, self).__init__(newgetter)
def setter(self, setter):
def newsetter(slf, newvalue):
oldvalue = self.fget(slf)
if oldvalue != newvalue:
setter(slf, newvalue)
slf.OnPropertyChanged(setter.__name__)
propagate_attributes(setter, newsetter)
return property(
fget=self.fget,
fset=newsetter,
fdel=self.fdel,
doc=self.__doc__)
From: Lukas Cenovsky [mailto:cenovsky at bakalari.cz]
Sent: Thursday, November 12, 2009 11:01 AM
To: Shri Borde
Subject: Re: [IronPython] .NET attributes for methods
Shri Borde wrote:
So the new clrtype.py still works - cool!
Yep ;-)
I am not an expert on data binding, so I don't have any suggestions. Why do you say that the decorator approach will not work with Silverlight? Does @notifiy_property from http://gui-at.blogspot.com/2009/11/inotifypropertychanged-in-ironpython.html use any feature not available in Silverlight?
It does not (as far as I know because it is pure IronPython). But @notify_property does not work with clrtypes:
class ViewModel(NotifyPropertyChangedBase):
__metaclass__ = clrtype.ClrMetaclass
_clrnamespace = "Cenda.ViewModel"
_clrproperties = {'size': str}
def __init__(self):
super(ViewModel, self).__init__()
# must be string to two-way binding work correctly
self.size = '10'
@notify_property
def size(self):
return self._size
@size.setter
def size(self, value):
self._size = value
print 'Size changed to %r' % self.size
When I run this code, the size is still clr property and Python getter and setter are not run.
So basically I need to override/enhance clr getter and setter created by clrtype._clrproperties.
--
-- Lukáš
From: Lukas Cenovsky [mailto:cenovsky at bakalari.cz]
Sent: Thursday, November 12, 2009 8:09 AM
To: Shri Borde
Subject: Re: [IronPython] .NET attributes for methods
Thanks, that works!
What do you think would be the best approach to create notifiable properties for Silverlight? I did it for WPF (via decorators: http://gui-at.blogspot.com/2009/11/inotifypropertychanged-in-ironpython.html) but it seems to me it won't be possible to do it similarly for Silverlight...
--
-- Lukáš
Shri Borde wrote:
Can you use "_clrproperties" instead of "_clrfields"? DevHawk's same created a field and a property even when you just used "_clrfields". I don't do that anymore. So you will need to use "_clrproperties" to get properties, which SL must use for data binding.
From: users-bounces at lists.ironpython.com<mailto:users-bounces at lists.ironpython.com> [mailto:users-bounces at lists.ironpython.com] On Behalf Of Lukas Cenovsky
Sent: Wednesday, November 11, 2009 2:37 AM
To: Discussion of IronPython
Subject: Re: [IronPython] .NET attributes for methods
I did change __metaclass__ to ClrMetaclass. See the attached source I use for testing - the only difference is to comment/uncomment appropriate part in product.py.
The outputs look the same, there are no visible exceptions:
DevHawk:
py> a.root.FindName('listbox1').ItemsSource[0].GetType().GetFields()
=> Array[FieldInfo]((<System.Reflection.RtFieldInfo object at 0x000000000000002B [Double cost]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002C [Int32 quantity]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002D [System.String name]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002E [IronPython.Runtime.Types.PythonType .class]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002F [IronPython.Runtime.PythonDictionary .dict]>,
<System.Reflection.RtFieldInfo object at 0x0000000000000030 [System.Object[] .slots_and_weakref]>))
Shri:
py> a.root.FindName('listbox1').ItemsSource[0].GetType().GetFields()
=> Array[FieldInfo]((<System.Reflection.RtFieldInfo object at 0x000000000000002B [Double cost]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002C [Int32 quantity]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002D [System.String name]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002E [IronPython.Runtime.Types.PythonType .class]>,
<System.Reflection.RtFieldInfo object at 0x000000000000002F [IronPython.Runtime.PythonDictionary .dict]>,
<System.Reflection.RtFieldInfo object at 0x0000000000000030 [System.Object[] .slots_and_weakref]>))
--
-- Lukáš
Shri Borde wrote:
Note that you will have to set __metaclass__ to ClrMetaclass, not ClrTypeMetaclass as in DevHawk's sample. I had changed the name of the type. The old name will cause a NameError, but maybe SL is hiding exceptions. Can you do "o.GetType().GetFields()" and display that on the page to inspect the object and also make sure that no exceptions were thrown?
From: users-bounces at lists.ironpython.com<mailto:users-bounces at lists.ironpython.com> [mailto:users-bounces at lists.ironpython.com] On Behalf Of Lukas Cenovsky
Sent: Tuesday, November 10, 2009 2:59 PM
To: Discussion of IronPython
Subject: Re: [IronPython] .NET attributes for methods
I have just found that the Silverlight binding does not work with this version of clrtype and/or IronPython 2.6RC2.
I used DevHawk demo [1] and after I added reference to Microsoft.Dynamic in clrtypemetaclass.py it worked flawlessly. But when I switch to your version, no items show in the listbox.
By the way - I have seen a commit message you have added support for interfaces - nice! ;-)
--
-- Lukáš
[1] http://cid-0d9bc809858885a4.skydrive.live.com/self.aspx/DevHawk%20Content/IronPython%20Stuff/^_^_clrtype^_^_/SL%20databinding%20demo.zip<http://cid-0d9bc809858885a4.skydrive.live.com/self.aspx/DevHawk%20Content/IronPython%20Stuff/%5E_%5E_clrtype%5E_%5E_/SL%20databinding%20demo.zip>
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