Attached Property Changed Handler

06 Feb 2016, 05:23

Hello,

1.- I have a custom-control in WPF where I can subscribe to the change notification of an attached property with this:

DependencyPropertyDescriptor.FromProperty(Canvas.LeftProperty, typeof (MyCustomControl)).AddValueChanged(Mydelegate);

But I couldn't find something similar, is there a way to do this with Noesis?

2.-While trying to use FocusManager.IsFocusScope in a xaml file, the resource build tool does not recognize it,
is there a namespace I need to add?

3.- I'm creating an user control is the OnPostInit method a good place to find some controls?

void DiagramEditor::OnPostInit()
{
	ParentClass::OnPostInit();

	m_canvas = FindName<Canvas>("TheCanvas");

	m_canvas->PreviewMouseWheel() += MakeDelegate(this,&DiagramEditor::OnEditorZoom);
}

also do I need to unsubscribe?, I'm asking this because of the trello https://trello.com/c/k7pREwVK/29-435-ci ... t-handlers

and if so, what would be the best overriding member method to do it ?

4.- this xaml is not setting the canvas left and top is not working

 <Ellipse  Fill="{StaticResource ConnectorColorBrush}" Height="10" Width="10" Name="Circle"
                     Canvas.Left="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=SourcePoint.X}"
                     Canvas.Top="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=SourcePoint.Y}">

this is the type of SourcePoint

	struct Point  : Drawing::Point
	{
		NS_IMPLEMENT_INLINE_REFLECTION(Point, Drawing::Point)
		{
			NsMeta<Core::TypeId>("Editor.Point");

			NsProp("X", &Point::GetX, &Point::SetX);
			NsProp("Y", &Point::GetY, &Point::SetY);
		}
        }

do you know why?

5.- Where can I see the binding errors ?

6.- how can I freeze a resource with noesis (I was told that is better to freeze the brushes for performance), in wpf I used to do this

 <ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:po="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:editor="clr-namespace:Editor">

    <SolidColorBrush x:Key="ConnectorColorBrush" Color="#888" po:Freeze="True" />

7.- it seems that

void OnPreviewMouseDoubleClick(const Gui::MouseButtonEventArgs& e) override;

is not working in controls

Thanks!.

08 Feb 2016, 11:32

Hi,

1. We don't have DependencyPropertyDescriptor implemented, could you please create a ticket in our bugtracker about this?

Right now the alternative in NoesisGUI are:

- If you want to know when a specific dependency property changes in you control, you can override the OnPropertyChanged method:

NsBool MyCustomControl::OnPropertyChanged(const DependencyPropertyChangedEventArgs& args)
{
  ParentClass::OnPropertyChanged(args);

  if (args.prop == Canvas::LeftProperty)
  {
    // ...
  }

  return false;
}

- If you want to subscribe to dependency property changes in a particular instance of your control from another class, you can use the public delegate DependencyPropertyChanged:

MyCustomControl* control = ...;
control->DependencyPropertyChanged() += MakeDelegate(this, &AnotherClass::OnCustomControlLeftChanged);
...
void AnotherClass::OnCustomControlLeftChanged(BaseComponent* sender,
  const DependencyPropertyChangedEventArgs& args)
{
  if (args.prop == Canvas::LeftProperty)
  {
    MyCustomControl* control = NsStaticCast<MyCustomControl*>(sender);
    ...
  }
}

2. FocusManager is not implemented in NoesisGUI, we have plans to include it in 1.3 version.
Now only Keyboard focus is available and you can access it from any UIElement instance:

UIElement* element = ...;
Keyboard* keyboard = element->GetKeyboard();
UIElement* focusedElement = keyboard->GetFocused();
keyboard->Focus(anotherElement);

3. The OnPostInit is a perfect place to find other controls, although we want to substitute that method in a future version with the WPF equivalent OnInitialized, that corresponds to the Initialized event. Another thing we have in mind is to generate automatically code that solves x:Name references in a xaml file to the appropriate member in the code-behind class, so you don't have to worry about doing the FindNames yourself.

The problem described in that Trello card refers to the Unity version, because C# keeps strong references when a delegate is attached to an event. In C++, our delegate system uses raw pointers to avoid the circular references. You don't need to unsubscribe if your instance (DiagramEditor instance) will be destroyed after the event holder (Canvas instance). If you think that event holder will raise the event after your instance is detroyed, you need to unsubscribe (usually in your class destructor) to avoid a crash.

4. This seems a bug, could you please report it in our bugtracker?

Anyway, this kind of binding won't be updated if SourcePoint values change as tthe struct is not a DependencyObject and cannot be a INotifyPropertyChanged object. I recommend to expose SourcePointX and SourcePointY as individual properties in your templated parent control.

5. In the Gui.XamlPlayer.ini you can specify a logfile, and enable binding warnings:

[Core.Logger]
Filename = "noesis.log"

[Gui.Binding]
LogWarnings = true

The generated log file is not a plain text file (uses an internal format for our debug tools), but can be opened with any text editor and you will see there all the messages, including information about any Binding that fails to solve and the reason.

6. Resources can't be frozen in XAML directly, you have to do it in code. Could you please add a ticket about the Freeze xaml option in our bugtracker, this seems an interesting feature to implement.

7. What do you mean? Is the virtual function not being called?
Are you injecting the double click to the IRenderer?

IRenderer* uiRenderer = ...;
uiRenderer->MouseDoubleClick(mousePos.x, mousePos.y, MouseButton_Left);

08 Feb 2016, 17:03

Hi, thanks for your responses

The bugtracker page keeps rejecting my credentials, is there something else I need to do to gain access?

08 Feb 2016, 17:23

Hi, thanks for your responses

The bugtracker page keeps rejecting my credentials, is there something else I need to do to gain access?

The bug tracker and the forum accounts are not linked. You need to create a new bug tracker account.

Maybe a good idea to add that info in a sticky topic and on the bug tracker log in page.

08 Feb 2016, 21:12

Thanks for the suggestion. I will create a sticky post with useful information about reporting a BUG in NoesisGUI, including the account creation detail.

09 Feb 2016, 04:01

Hi Again!

1.-Is this a correct behaviour :

this method is subscribed to changes of both collections , and my intend was to do a dynamic_cast to determine which of both is the collection that raised the handler, but both return not null

2.- While trying to do this

<editor:Connector Source="{Binding ElementName=DesignerItem}"  TargetPoint="400,400"  Text="Jump" />

I get the following error:

  Parsing Editor.Connector.TargetPoint (@21,12).
1>    '400,400' is not a valid value for property 'Editor.Connector.TargetPoint'

do I need to provide a converter?, this type of automatic conversions are common in xaml & wpf.

11 Feb 2016, 16:46

1. It's not the expected behavior. I confirmed that the ObservableCollection class doesn't have the reflection marks specified, that's why it is returning the base class type (Collection) when doing a dynamic cast. We will solve this for the next version.

Meanwhile you have to subscribe using different methods for each ObservableCollection type.

2. How is TargetPoint type declared? Is inheriting from Noesis::Drawing::Point or is a new type?

If it is a new struct type you need to define a method like this:

static NsBool TryParse(const NsChar* str, TargetPoint& result);

And register the converter for that type in your dll:

extern "C" NS_DLL_EXPORT
void NsRegisterReflection(ComponentFactory* factory, NsBool registerComponents)
{
  // ...
  NS_REGISTER_COMPONENT(Noesis::Core::Converter<Editor::Connector::TargetPoint>)
}

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