XAML extension question

  • Thread starter Thread starter Lloyd Dupont
  • Start date Start date
L

Lloyd Dupont

In my application I want to display some data in a list box.
I need to display the data as a picture.

My 1st idea was to create a ValueConverter to convert my datas to
ImageSource
But this has a few problem, the biggest one is there is no parameter!
So I though of MarkupExtension
something like that:
<ListBox ItemsSource={Binding Document.Maps}>
<ItemTemplate>
<Image Source="{local:Map2Image PreviewDpi=24, Background=false}" />
</ItemTemplate>
</ListBox>

but here, problem, in the Map2ImageExtension.ProvideValue(IServiceProvider)
I don't ave the current data, worst, I have no idea to get it.

I was able to get the IProvideValueTarget but it only knows about the
"Image" object, not about the current item.
I tried to look into the "Binding" and "BindingBase" code with reflector,
but I don't understand what's going on...
Any tip?


Otherwise I could write a specialized viewer FrameworkElement, but I though
of using MarkupExtension might be a nice way to solve the problem....
 
Hi Lloyd


I don't have an answer to your problem. Sorry.
But today I have the same problem and don't know how to get the instance of
the ServiceProvider.

In my case I want get the "ObjectDataProvider"
How can tell us how we can get our ServiceObjects?


My Xaml:

<ObjectDataProvider x:Key="VitoPatient" ObjectType="{x:Type
VFC:GetDataCommand}" MethodName="Execute">
.....

<StackPanel VFW:DesignView.DataContext="{Binding
Source={VFW:MyDynamicResource VitoPatient},
Path=ParentObjects[Person__Patient]}">
.....

My Class:

<MarkupExtensionReturnType(GetType(Object)),
TypeConverter(GetType(DynamicResourceExtensionConverter))> _
Public Class MyDynamicResource
Inherits System.Windows.DynamicResourceExtension

Public Overrides Function ProvideValue(ByVal serviceProvider As
System.IServiceProvider) As Object
If (Not VitoResourceManager.DesignMode) Then
If (GetType(ObjectDataProvider).IsInstanceOfType(serviceProvider))
Then
Return MyBase.ProvideValue(serviceProvider)
Else
Return MyBase.ProvideValue(serviceProvider)
End If
Else
Return VitoApplication.FindDynamicResource(Me.ResourceKey.ToString)
End If
End Function

Public Sub New()
MyBase.New()
End Sub

Public Sub New(ByVal resourceKey As Object)
MyBase.New(resourceKey)
End Sub

End Class
 
Hi,

--
Hi Lloyd


I don't have an answer to your problem. Sorry.
But today I have the same problem and don't know how to get the instance
of
the ServiceProvider.

In my case I want get the "ObjectDataProvider"
How can tell us how we can get our ServiceObjects?
Click to expand...
when I read you VB code it looks a bit strange to me... :-/
anyway here is pseudo C# code (i.e. from the top of my head) to lookup for
object by name (define before the object using this markp extension, same
restriction as in StaticResource)

class MyMarkup : MarkupExtension
{
public object ProvideValue(IServiceProvider sp)
{
if(sp == null)
return null
IProvideValueTarget pvt =
(IProvideValueTarget)sp.GetService(typeof(IProvideValueTarget));
if(pvt == null)
return null;
FrameworkElement fe = pvt.Target as FrameworkElement;
if(fe == null)
return null;

DependencyObject do = fr.FindName("aName");
// ... whatever you need to ...
}
}
 
Hi Lloyd

Thanks a lot that looks good to get the TargetObjetct.

But How can I get the Source?

In my case the
<ObjectDataProvider x:Key="VitoPatient" ObjectType="{x:Type
VFC:GetDataCommand}" MethodName="Execute">

Best regards Horst
 
mmhh... I don't understand the question?..
what is this source you talk about?

anyway your only hope is a FindName() (or FindResource()) call to get other
object on the UI.
Binding use an internal Expression class which sets up event listener and
can
 
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