[Ironpython-users] Embedded IronPython, Properties with Custom Attributes, __clrtype__ and PropertyGrid

[Borut Jarc]

Hello,

I'm Borut Jarc and I work at A.S.U.I.Ts (Azienda Sanitaria Universitaria
Integrata di Trieste) as a Domain Admin.

I'm writing an C# 4.0 application to help my Network Admins to manage the
subnets configured on our network switches.
The application has Iron Python embedded, a simple plugin system and a
plugin manager. The plugins are written in IronPython.
Everything works fine so now I am writing a configuration dialog for the
plugins properties.
I'm trying to use a PropertyGrid which I give an instance of an IronPython
class.

To make use of all the nice features of PropertyGrid like Description,
Category and PasswordPropertyText i extended the ClrClass from clrtype
module from clrtye sample, implemeting the emit_property method as follows:


class MyClrClass(ClrClass):
    def emit_property(self, typebld, prop, name, clrtype):
        prpbld = typebld.DefineProperty(name, PropertyAttributes.None,
clrtype, None)
        if prop.fget:
            getter = self.emitted_methods[(prop.fget.func_name,
prop.fget.arg_types)]
            prpbld.SetGetMethod(getter)
        if prop.fset:
            setter = self.emitted_methods[(prop.fset.func_name,
prop.fset.arg_types)]
            prpbld.SetSetMethod(setter)
        if hasattr(prop.fget, "CustomAttributeBuilders"):
            for cab in prop.fget.CustomAttributeBuilders:
                prpbld.SetCustomAttribute(cab)

then in my IronPython script I define the class:

class OSCommware7_ssh(PluginBase):
    __metaclass__ = clrtype.MyClrClass
    _clrnamespace = "PianoIndirizzamentiIP_Tool"
    _clrfields = {"_username":str,
                  "_password":str,
                  "_prompt":str}

    Description = clrtype.attribute(DescriptionAttribute)
    Category = clrtype.attribute(CategoryAttribute)

    @property
    @Category("Credentials")
    @Description("Username for login on Core Switch")
    @clrtype.accepts()
    @clrtype.returns(str)
    def username(self): return self._username
    @username.setter
    @clrtype.accepts(str)
    @clrtype.returns()
    def username(self, value): self._username = value

     ....
(PluginBase is the c# class with acts as the plugin skeleton. Contais also
some plugin helper functions (password encryption decryption))

and in my c# code I do something like:

...
 _engine = Python.CreateEngine();
 _scope = _engine.CreateScope();
 _runtime = _engine.Runtime;

 _root_dir = AddAssemblies();

 _scope = _engine.CreateScope();

...

 ScriptSource script =
_engine.CreateScriptSourceFromFile(path_to_python_script);
 CompiledCode code = script.Compile();
 script.Execute(scope);

...

dynamic plugin_instance = my_engine.scope.GetVariable("OSCommware7_ssh")()
propertyGrid1.SelectedObject = plugin_instance;
 ...

If I inspect plugin_instance with
(System.Reflection.PropertyInfo[])(plugin_instance.GetType().GetProperties()):

-
((System.Reflection.PropertyInfo[])(plugin_instance.GetType().GetProperties()))[3]
{System.String
username} System.Reflection.PropertyInfo
{System.Reflection.RuntimePropertyInfo}
Attributes None System.Reflection.PropertyAttributes
CanRead true bool
CanWrite true bool
- CustomAttributes Count = 2
System.Collections.Generic.IEnumerable<System.Reflection.CustomAttributeData>
{System.Collections.ObjectModel.ReadOnlyCollection<System.Reflection.CustomAttributeData>}
+ [0] {[System.ComponentModel.DescriptionAttribute("Username for login on
Core Switch")]} System.Reflection.CustomAttributeData
+ [1] {[System.ComponentModel.CategoryAttribute("Credentials")]}
System.Reflection.CustomAttributeData
+ Raw View
+ DeclaringType {Name = "OSCommware7_ssh" FullName =
"PianoIndirizzamentiIP_Tool.OSCommware7_ssh"} System.Type
{System.RuntimeType}
+ GetMethod {System.String username()} System.Reflection.MethodInfo
{System.Reflection.RuntimeMethodInfo}
IsSpecialName false bool
MemberType Property System.Reflection.MemberTypes
MetadataToken 385875970 int
+ Module {Snippets.scripting} System.Reflection.Module
{System.Reflection.Emit.InternalModuleBuilder}
Name "username" string
+ PropertyType {Name = "String" FullName = "System.String"} System.Type
{System.RuntimeType}
+ ReflectedType {Name = "OSCommware7_ssh" FullName =
"PianoIndirizzamentiIP_Tool.OSCommware7_ssh"} System.Type
{System.RuntimeType}
+ SetMethod {Void username(System.String)} System.Reflection.MethodInfo
{System.Reflection.RuntimeMethodInfo}
+ Non-Public members


I see all the properties and their CustomAttributes set as expected, but
for some reason PropertyGrid simply ignore them.

I feel like I'm missing something important but I don't know what.

Can someone explain me what I'm doing wrong?

Thank you and forgive my poor English...

Borut Jarc
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