https://msdn.microsoft.com/en-us/magazine/dd419663.aspx

written by Josh Smith. He has written lots of articles on WPF.

You can view them at his blog joshsmithonwpf.wordpress.com

Writing More Efficient ItemsControls

https://msdn.microsoft.com/en-us/magazine/dd483292.aspx

from Charles Petzold

Win+Home: Clear all but the active window

Win+Space: All windows become transparent so you can see through to the desktop

Win+Up arrow: Maximize the active window

Win+Down arrow: Minimize the active window or restore the window if it's maximized

Win+Left/Right arrows: Dock the active window to each side of the monitor

Win+Shift+Left/Right arrows: If you've got dual monitors, this will move the active window to the adjacent monitor

Win+T: Shift focus to and scroll through items on the taskbar

Win+P: Adjust presentation settings for your display

Win+(+/-): Zoom in/out

Shift+Click a taskbar item: Open a new instance of that particular application

   1: public static class DependencyPropertyHelper

   2: {

   3:     // Methods

   4:     public static ValueSource GetValueSource(DependencyObject dependencyObject, DependencyProperty dependencyProperty);

   5: }

It just has one static method called GetValueSource and the parameters is dependencyObject instance and dependencyProperty instance.

The type of return value is ValueSource:

   1: public struct ValueSource

   2: {

   3:     public BaseValueSource BaseValueSource { get; }

   4:     public bool IsExpression { get; }

   5:     public bool IsAnimated { get; }

   6:     public bool IsCoerced { get; }

   7: }

   8:  

   9: public enum BaseValueSource

  10: {

  11:     Unknown,

  12:     Default,

  13:     Inherited,

  14:     DefaultStyle,

  15:     DefaultStyleTrigger,

  16:     Style,

  17:     TemplateTrigger,

  18:     StyleTrigger,

  19:     ImplicitStyleReference,

  20:     ParentTemplate,

  21:     ParentTemplateTrigger,

  22:     Local

  23: }

It contains some read-only properties. If you have time, you can use this method to get

the ValueSource of targetButton’s Width Property(code is attached in the preview post).

And you will understand the DependencyProperty precedence better!

I have tried and find that In some scenario, IsAnimation = true and IsCoerce = true.

In the precedence list, the coercion source is the highest.

In order to verify it, I have created a class called CoercionButton.

   1: public class CoercionButton : Button

   2: {

   3:     static CoercionButton()

   4:     {

   5:         WidthProperty.OverrideMetadata(typeof(CoercionButton), new FrameworkPropertyMetadata(null, OnCoerceValueCallback));

   6:     }

   7:  

   8:     // public delegate object CoerceValueCallback(DependencyObject d, object baseValue);

   9:     public static object OnCoerceValueCallback(DependencyObject d, object baseValue)

  10:     {

  11:         return 150.0;

  12:     }

  13: }

It overrides the Metadata of WidthProperty and adds CoerceValueCallback. And in the callback, returns a constant value 150.0.

We change the “Target Button” from normal Button type to CoercionButton type.

But the event handler for other 4 buttons remain some.

No matter which button you clicks, the Width of “Target Button” is always 150.

And the animation doesn’t work.

I have create a simple solution to go deep on coercion, animation and local value. You can download it by clicking following link. (it’s on Microsoft SkyDriver.)

In this solution, there are 2 projects.

Let’s focused on the WpfAnimationAndLocalValue project first(Another project will explained in the next post)

The snapshot of this program:

There are 4 buttons you can click:

“Start animation” button(Button 1) :

   1: private void StartAnimation(object sender, RoutedEventArgs e)

   2: {

   3:     DoubleAnimation doubleAnimation = new DoubleAnimation(300, new Duration(TimeSpan.FromSeconds(2)), FillBehavior.HoldEnd);

   4:     targetButton.BeginAnimation(Button.WidthProperty, doubleAnimation);

   5: }

    just apply double animation to Width property of TargetButton(its FillBehavior is HoldEnd)

“Set Width of Target Button to 200” button(Button 2)

   1: private void SetButtonWidth(object sender, RoutedEventArgs e)

   2: {

   3:     targetButton.Width = 200;

   4: }

“Clear Animation(Copying Value)” button (Button 3)

   1: private void ClearAnimationWithCopy(object sender, RoutedEventArgs e)

   2: {

   3:     targetButton.Width = targetButton.ActualWidth;

   4:     targetButton.BeginAnimation(Button.WidthProperty, null);

   5: }

“Clear Animation” button(Button 4)

   1: private void ClearAnimation(object sender, RoutedEventArgs e)

   2: {

   3:     targetButton.BeginAnimation(Button.WidthProperty, null);

   4: }

Then following the below steps:

Step 1: Click button 1 (animation starts and Width increased to 300)

Step 2: Click button 2 (No change on the Width)

This is the problem described at the start of this post. The root cause is that

Animation value source has higher priority than local value. So the code

 targetButton.Width = 200; 

has change the local value. 

But the effective value of Width comes from animation source.

Step 3: Click button 4 (the Width changes to 200)

After removing the animation, the effective value of Width is re-calculated.

In this time, the local value is the source of effective value and since we has

changed the local value of Width to 200. So the effective value of Width is 200.

Step 4: Click button 1 again(animation starts and Width increased to 300)

Step 5: Click button 3 (No change on the Width)

  this step needs some explanations. 

   1: targetButton.Width = targetButton.ActualWidth;

   2: targetButton.BeginAnimation(Button.WidthProperty, null);

Before removing animation, set the Width using ActualWidth.

so it updates the local value of Width to effective value provided by animation.

After removing animation, the local value becomes effective value of Width.

So no change on the Width.

You can compare this step 5 with step 3.

Step 6: Click button 2(change Width to 200)

 Since we remove the animation, we can change the value now.

In this blog, I focus on the precedence list when calculating the value of DependencyProperty.

Highest precedence is listed first:
From msdn:
https://msdn.microsoft.com/en-us/library/ms743230.aspx

1 Property system coercion

2 Active animations or animations with a Hold behavior

3 Local value

4 TemplatedParent template properties

5 Implicit style

6 Style triggers

7 Template triggers

8 Style setters

9 Default(theme) style

10 Inheritance

11 Default value from dependency property metadata

In the next post, I will show some code to go deep.

https://msdn.microsoft.com/en-us/magazine/cc135865.aspx

Also you can download them(.chm files) at

https://msdn.microsoft.com/en-us/magazine/cc159440.aspx

Enjoy!

The answer is DeepEarth.

“ DeepEarth is a mapping control powered by the combination of Microsoft’s Silverlight 2.0 platform and the DeepZoom (MuliScaleImage) control. At its core, it builds on these innovative technologies to provide an architecture for bringing together layers for services, data providers, and your own custom mapping elements together into an impressive user experience. Also featured are in depth examples of how you can leverage Virtual Earth Web Services to take advantage of advanced GIS service functionality. This is what you need to get an interactive, native Silverlight 2.0, map into your application today.”

Read the article at InfoQ, click here

The project home is at https://www.codeplex.com/deepearth

And you can view the example at

https://deepearth.soulsolutions.com.au/

In this online demo, I think the control on the top-left corner is cool.

You can view it at:

https://msdn.microsoft.com/en-us/magazine/dd263097.aspx?pr=blog

I create a xps version, you can download from my skydriver by clicking below link:

Very Cool!