Trips&Ticks: Do you know how you can cast Object to AnonymousType?

I experimented with LINQ in my private project and question that was showed in title took me. I had next situation:

I set list in one method:

private void SetList()
{
SomeList.ItemsSource = ( from someTable in data.SomeTable
select new
{
someTable.Id,
someTable.Name,
Priority = someTable.Priority,
} );
In other method I want retrieve Id of selected item. How can I do it? I have found interesting solution in blog of Tomas Petricek.
private Int32 GetID()
{
Object selectedItem = DefectList.SelectedItem;

if( null != selectedItem )
{
var item = Utility.Cast( selectedItem, new
{
Id = 0,
Name = String.Empty,
Priority = String.Empty,
} );

Int32 id = item.Id;
}
}
public static T Cast( object obj, T type )
{
return (T)obj;
}

PS: As for me the best way is:

• implement class with three like property.
• create collection with items of this class.
• set in ItemsSource new created collection.
• now we can easy case Object to this class.

Such different paths. Binding in WPF part 1.

Download source files - here

We pleasure to using Binding in WPF. But all ways of using have we known? Only direct binds to dependency property like next code?

<TextBlock Text="{Binding Path=Height, ElementName=myButton}">

This is poor. We can bind to property of value's property. How?
Easy:

<TextBlock Text="{Binding Path=Background.(SolidColorBrush.Opacity), ElementName=myButton}"/>

and

<TextBlock Text="{Binding Path=(Button.Content).(TextBlock.FontSize), ElementName=myButton}"/>

In attached sample I show how we can use this for EventTriggers.

Trips&Ticks: Do you know how do you need to change properties of local file when it will be loaded, using a Relative Uri?

When I had tried to use Relative URIs for local files I found next trouble - resource wasn't found in my app. Solution for this problem is next actions: we should open properties of local file and change flag named "Copy to Output Directory" from "Do not Copy" to "Copy always".
Easy and logically.

PS: Nice article about URI in WPF - Pack URIs in Windows Presentation Foundation

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.

Little deception of List.ForEach(Action action)

I use foreach statement really often. It is useful and more compact than for. (This way is fast in same case but in same case it is slowly for performance. But I want say not about that). List<T> class has ForEach(Action action) method I thought that its implementation (and behaviour) is like foreach statement (I make this conclusion, based on the name of method) but I was confused. I have looked to Net. Reflector and saw next code:

public static void ForEach(T[] array, Action action)
{
if (array == null)
{
throw new ArgumentNullException("array");
}
if (action == null)
{
throw new ArgumentNullException("action");
}
for (int i = 0; i < array.Length; i++)
{
action(array[i]);
}
}

ForEach(Action action) method behaviour likes for statement behaviour. And I can use it like for. For example I can change main collection during execution action delegate.

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 ;)

Correct use ItemsSource in WPF for controls inherited from ItemsControl

I sometimes read MSDN forums of WPF. I have founded post with interesting problem. I was interested this trouble.

We can download sample from there. Pay attention that ListView have strange behavior: pressing "s" moves the focus to the next item. I was interested this problem and little investigate it. This action relations with search functionality. If we don't need search functionality we can easy fix it, override ToString() method:

public override string ToString()
{
return string.Empty;
}

FYI:
If you need more details why does it do, you can read next:

After you type letter 's', next methods were called:
...................
- void OnTextInput( TextCompositionEventArgs e ) of ItemsControl;
- bool DoSearch(string nextChar) of TextSearch;
- int FindMatchingPrefix(ItemsControl itemsControl, string primaryTextPath, string prefix, string newChar, int startItemIndex, bool lookForFallbackMatchToo, ref bool wasNewCharUsed) of TextSearch;

- string GetPrimaryText(object item, BindingExpression primaryTextBinding, DependencyObject primaryTextBindingHome) of TextSearch
private static string GetPrimaryText(object item, BindingExpression primaryTextBinding, DependencyObject primaryTextBindingHome)
{
//item is EmployeeInfo (!!)
DependencyObject obj2 = item as DependencyObject;

if (obj2 != null) // false
{
string str = (string) obj2.GetValue(TextProperty);
if (!string.IsNullOrEmpty(str))
{
return str;
}
}
if ((primaryTextBinding != null) && (primaryTextBindingHome != null)) //false
{
primaryTextBinding.Activate(item);
return ConvertToPlainText(primaryTextBinding.Value);
}
return ConvertToPlainText(item); //It was called
}

-string ConvertToPlainText(object o) of TextSearch
private static string ConvertToPlainText(object o)
{
FrameworkElement element = o as FrameworkElement;
if (element != null) //false
{
string plainText = element.GetPlainText();
if (plainText != null)
{
return plainText;
}
}
if (o == null) // false
{
return string.Empty;
}
return o.ToString(); //return "SDKSample.EmployeeInfo"
}


- In this FindMatchingPrefix method we prepare this string as follows
........................
string str2 = GetPrimaryText(obj3, bindingExpr, itemsControl);
if ((str2 != null) && str2.StartsWith(str, true, culture)) //"SDKSample.EmployeeInfo" is started with "s" ;) (!!!!!)
{
wasNewCharUsed = true;
num = num4;
break;
}
........................
return num;

- and in the DoSearch(string nextChar) method
........................
int itemIndex = FindMatchingPrefix(this._attachedTo, primaryTextPath, this.Prefix, nextChar, startItemIndex, lookForFallbackMatchToo, ref wasNewCharUsed);

if (itemIndex != -1)
{
if (!this.IsActive || (itemIndex != startItemIndex))
{
object item = items[itemIndex];

this._attachedTo.NavigateToItem(item, itemIndex, new ItemsControl.ItemNavigateArgs(Keyboard.PrimaryDevice, ModifierKeys.None)); //wrong code is started
this.MatchedItemIndex = itemIndex;
}

........................

Nothing is perfect..