Trouble with resources in WP7

I started a few projects on WP7. It was done just for fun and for improving my skills (Fun was profitable - I won in Ukrainian WP7 competition). So I had completed my projects and tried to localize it.

I met some issues:

1. If you have experience in developing for web silverlight - first isn't new for you. When I edit/add/remove a item in resources's file I need to open resources designer's file and change access modifiers of parameterless constructor from "internal" to "public".
   It is know issue and know fix - proof.
   
2. Second was new for me. It is strange issue because it appeared only in one of my projects. I created resources file and added key in Resources section of app.xaml (for binding to resources in my xaml files). My project started to crash after this.
   I had spent some time and found source of the issue. I noticed that Resource class (auto generated) is internal. I checked "Custom tool" field in properties of resource file. It was filled "ResXFileCodeGenerator" value. In my other projects this field contained "PublicResXFileCodeGenerator" value. I didn't found detailed description of "ResXFileCodeGenerator" but looks like that it is obsolete tool. I no idea how to it was set in my project.

One more note: it is for WP7 without "Mango" update. I hope I will not meet such issues after this update.

Trips&Ticks: Easy way to navigate from XAML to class's definition.

Working with XAML code in VS2008 I have just found that I can easy jump to class's or property definition. If I press CTRL and click left mouse button on certain class or property in XAML I will be immediately switched to Object Browser (if it is class or property of .NET or external dll) or to class's or property definition in my code (if it is class or property from my sources).

Eugene Dolinskyy just pay my attention that "clear" VS2008 doesn't have this possibility. This feature is presented by ReSharper.

This whimsical binding. TwoWay Binding to DataContext. Binding in WPF part 3.

I often use Binding to DataContext. It is one of the main advantage of WPF. In most case I set custom class inherit of DependencyObject (for support DependencyProperty) and I have some like next code:

<StackPanel>
<TextBlock Text="{Binding Path=Id}" />
<TextBlock Text="{Binding Path=Name}" />
<TextBlock Text="{Binding Path=Surname}"/>
...
</StackPanel>

But sometime I set a simple type for example string. For this case I can implement next Binding:

<TextBlock Text="{Binding}" />

Note: Pay attention, when we bind directly to DataContext I have written a short form (only 'binding' keyword).

But when I try to implement TwoWay Binding to DataContext. I have exception - "Two-way binding requires Path or XPath.". It cannot set a value from somewhere because it doesn't know where it came from. I can easy fix it. For example property IsChecked of CheckBox has request TwoWay Binding in metadata. For this case I have written next code:

<CheckBox IsChecked="{Binding Path=DataContext, RelativeSource={RelativeSource Self}}">

It is not so graceful, but it works.

Implementing support of own child/children in WPF control.

Download source files - here
Download bin files - here

The best way for use child/children in WPF is customize any control with property for child/children that inherit from Control (for example ContentControl or ItemsControl). Control has wide possibility of customizing through ControlTemplate. But sometime we want to have a specific behaviour of child/children (for example if we want to implement MDI container any other specific container). What should you do for implementing this behaviour? I will show major steps in sample of simple custom panel that is inherited from FrameworkElement.

1. First of all you should add property according type that will be contain child/children. I use Children property in my sample. It is list of UIElement. I use ObservableCollection because I need to react to collection change.
   
2. You should see to show child/children in your control, you should override int VisualChildrenCount and Visual GetVisualChild( int). These method and property should get value accordingly with child/children property (child/children's count and this/these element/s according to index).
3. Your app can correct build now but still nothing shows in app when it is run. It is happened because child/children doesn't/don't know their size and position on parent. You should override Size MeasureOverride(Size) for pass size (and calculate DesiredSize in child) to child's element and Size ArrangeOverride(Size) for pass position on parent. When you run app again you can see child/children in your custom control. You should point out to sizes that are returned in these method, MeasureOverride's size says to parent DesiredSize of your custom control and ArrangeOverride says to parent square that were taken.
4. Now you can see that your custom control is run correct, but when you try to interact with their child/children you can see that interact is fail. It is happened because child/children property isn't/aren't added to visual tree of your custom control. AddVisualChild(Visual) method helps you in this. The best way is realized this behavior in property changed method for child or collection changed method for children. Pay attention that property changed isn't called for default value for your child/children property. We have some other reason set null as default value, but I say below about it.
5. If you test your custom control more careful you can observe that interaction isn't complete. Yeah, visual interaction you have already implemented, but logical isn't complete. How can you observe it? Easy, try to use attached and inherit properties or DataContext - they don't work. You should add child/children to logical tree of your custom control. AddLogicalChild(Object) helps. You can call this method together with AddVisualChild.
6. Be careful, if you want to remove element from child/children you shouldn't remember that this element should be removed from visual tree and logical tree. RemoveVisualChild(Visual) and RemoveLogicalChild(Object) help you in this.
7. Interaction works correct now, but you can see new trouble, if you add/remove child/children in run-time you can't see any visual effect until do any change of size in app. It is happen because your custom control knows nothing about this add/remove action. If you are implementing child you can add AffectsArrange and AffectsMeasure flag to metadata of child property, they mean that custom control should do arrange and measure after each property change. If you are implementing children you should call InvalidateVisual() after each collection change. Added/Removed item shows/disappears immediately now.
   
8. If you want set child/children property through XAML you should explicitly set your child/children property. You can apply to your custom control attribute ContentPropertyAttribute. So you can implicitly set your child/children property.
9. In point #4 I have promised to say why you can't set default value no null. Pay attention that Dependency property is static member of class, so refer of one default value is added to all instances of your custom class. So you should use type that inherit form ValueType as type of dependency property or reinitialize default value in constructor (You should chose second way:).
10. My coworker have found interesting trouble with RightToLeft support. His custom control can correct support RightToLeft only after he overrides LogicalChildren property. I can't reproduce it, but want to inform about possible trouble and solution for it.

I have written detailed road map with explanations. If some details aren't clear you can download sample with source code (case with children is implemented there).
Good luck!

Trips&Ticks: Do you know how you can break text in any text control of WPF?

Seems it is easy - we can use a LineBreak in code or as XAML element, but what can we do if we want to present this in attribute of XAML? Little searching shows that we should use XSLT and hexadecimally encoded value to present a literal.
<TextBlock Text="Line 1&#x0A;Line 2" />

Trips&Ticks: Do you know how can you obtain access to nested types through XAML?

Download source files - here.

XAML is a declarative XML-based language created by Microsoft which is used to initialize structured values and objects. I have already written how we can obtain access to properties of instance that located in other properties here (I have described binding's potential). But what can we do if we need to access to nested type? Which syntax should me use? It is easy: "+" indicates nested type in XAML:

local:MultiLevelButton+NestedInfo.NestedName

A lot of code snippets you can see in sources.

Trips&Ticks: Do you know how you can extract various instances of one object out of resources in WPF?

Download source files - here

I often use a style&template that is magnificent possibility of WPF. It allows to define one style out of resources to many elements. I can easily define instance of some object in resources and extract it there where I require. But it has one limitation:
For example for following:

XAML:
<Button x:Key="ButtonPrototype" />

C#:
Resources["ButtonPrototype"]; - returns always one instance (like Singlton Pattern). But what can I make if I require more than one such object? It isn't problem as XAML is very flexible and x:Shared attribute eliminates this trouble. Following code will extract various instances:

XAML:
<Button x:Key="ButtonPrototype" x:Shared="False" />

C#
Resources["ButtonPrototype"]

PS: In my opinion last realization shares traits with Prototype Pattern.

Really multiUI window in WPF project.

Download binary file - here
Download source files - here

Introduction.
WPF presents new way to implement visual appearance of application. We can implement it in XAML and C# files both or separately. We use Application.LoadComponent( Object, Uri ) method for load XAML files where "Uri" presents way to XAML file. So we can manipulate visual appearance presented in XAML's files load different XAML's files.

Note: We can't use x:Class attribute for root node in XAML's files. In this case compiler automatic generates C# code (in *.g.cs file) and those classes will be conflicted (more precisely - some automatic generated members will be conflicted). Thus we can't use x:Code and describe to events in XAML's files (code for support those actions were implemented in *.g.cs files).

Note: Class have been generated in XAML's file (more precisely - in *.g.cs) is normal class likes class have been generated in C# code and even we can inherit a custom class from it.

My sample.
My sample presents two mode for manager and worker that to show the personal's information. We load different XAML's files against of mode. First we show dialog window that propose to choose behaviour.

Different XAML's contains different class instants for present data:
PeopleEx (People - for worker) - presents data of personnel (less for worker and more for manager).
ManagerInfoPresenter (WorkerInfoPresenter - for worker) - get a information (different for other mode).
ManagerCapacityShow (WorkerCapacityShow - for worker) - show a diagram. It is fake but it is different for other mode.

We can implement different controls with one name in other XAML's files (for example "InformCheck" or "CapacityShow"). We found those controls in XAML's files to use FindName(String) method and we can handle some events of this controls.

CheckBox informer = (CheckBox)FindName( INFORMCHECK_NAME );
informer.Checked += new RoutedEventHandler( OnInformerChecked );
informer.Unchecked += new RoutedEventHandler( OnInformerUnchecked );

We can apply to different class members to use base class (like m_CapacityShow member) or interface (like m_InfoPresenter member).

if( AppMode.Manager == appMode )
{


...
m_InfoPresenter = new ManagerInfoPresenter();

}
else
{

...
m_InfoPresenter = new WorkerInfoPresenter();

}
...
m_CapacityShow = (Image)FindName( CAPACITYSHOW_NAME );

Summary
We can really create one class window for two (or more) behaviour of application. We don't hide any controls or elements we don't load they! It is elegant way to dynamic create application.

My version of Snoop (+ 2 features) of WPF

I think that every WPF developer knows that is Snoop. This is helpful tool (with source code (!!) ) for visual debugging of WPF's app at runtime. It is good but I was in need of some expansions.

1. I needed to see Template of controls in visual tree.
2. I needed to keep a/some couple (value and property) of control in visual tree.
   

I implemented this issues for self purpose and want to impart this to all.

At first. My coworker Ivan and ex-coworker Eugene implemented like issue. But their solution didn't satisfy me. It had low performance. I re-implement it and in my solution convert to xaml come true after click to "Show XAML!" button only. It increase performance in comparison with previous solutions.


For second feature I used code of Beatriz Costa that allows you to drag and drop items between data bound ItemsControls (I added a little modification for my purpose only). I added new PropertyGrid. We can drag a item from main PropertyGrid to keep PropertyGrid.

In last PropertyGrid property saves relation with its owner even if it contains different owners of properties.

Here you can find the project with this features built using VS2008.

Enjoy ;)