WPF Control Development Unleashed

Pavan Podila, Architect at NYC’s Liquidnet Holdings, has worked extensively with many leading UI technologies, including WPF/Silverlight, Flash/Flex/AIR, and DHTML. In the past, he has worked with Java Swing, Eclipse SWT, and TrollTech/Nokia Qt. His primary interests include 2D/3D graphics, data visualization, UI architecture, and computational art. He created FluidKit (http://fluidkit.codeplex.com), an open-source WPF library of controls such as ElementFlow, TransitionPresenter, etc. He is a Microsoft MVP for Client App Dev and blogs actively at http://blog.pixelingene.com.   Kevin Hoffman got his first computer, a Commodore VIC-20, when he was 10 years old and has been hopelessly addicted to programming ever since. He has written desktop applications, web applications, distributed enterprise applications, VoIP software, and pretty much everything else in between. He is currently a .NET Architect in New England building large-scale, next-generation web applications.  

About the Authors          xii

Dedications           xiii

We Want to Hear from You!        xv

Part I Thinking in WPF

1 The WPF Design Philosophy 1

Data and Behavior           2

Working with Data          3

Templates            3

Presenters            4

Binding and Converters         4

Layout            5

Styles            5

Working with Behaviors          6

The User Experience          8

The User Experience Benevolent Circle       9

A Note on Sample Source Code       9

Summary           10

2 The Diverse Visual Class Structure 11

Introducing the Visual Classes        11

The DispatcherObject Class        12

The DependencyObject Class        12

The Visual and DrawingVisual Classes       13

The FrameworkElement Class       15

The Shape Class          16

The Text Classes          18

The Control Class         19

The ContentControl Class         20

The ContentPresenter Class        20

The ItemsControl Class         21

The UserControl Class         22

The Panel Class          23

The Decorator Class          24

The Adorner Class         24

The Image Class          25

The Brushes          25

The DataTemplate, ControlTemplate, and ItemsPanelTemplate Classes        27

The Viewport3D Class         27

The MediaElement Class        28

The InkCanvas          28

Summary           29

3 Getting Started Writing Custom Controls 31

Overcoming the “Start from Scratch” Instinct     31

Using Data Transformations        32

Find the Behavior You Want, Then Extend     34

The Power of Attached Properties       35

Custom Control Creation Checklist      38

Thinking in Layers–The Art of Decomposition    39

Sample: Building a Circular Minute Timer      40

Enhancing and Extending the ProgressBar     40

Creating the Arc Shape         42

Working with the ControlTemplate      43

Summary           47

4 Building Custom Panels 49

Layout Defined          49

How Layout Works          51

Working with Visual Children        52

Creating a Custom Panel: The VanishingPointPanel     56

Building a Panel with Attached Properties: WeightedPanel    58

Using Transformations with Layout       63

Enter the LayoutTransform        66

Layout Events           66

Summary           68

5 Using Existing Controls 69

Customizing Existing Controls        70

Customizing Controls Using Properties      70

Customization Using Control Templates      70

Customization with Data Templates      71

Using a ControlTemplate and a DataTemplate     71

Customizing the ItemsControl        72

Customizing a ListBox          74

Customizing the ItemContainerStyle      74

Customizing the ItemTemplate and the ItemsPanelTemplate  77

Creating a Custom ScrollBar         78

Using Brushes to Create Advanced Visuals      82

Using the VisualTreeHelper and LogicalTreeHelper    82

Customization Sample–The Radar Screen      83

Moving Enemies in a ListBox        84

Concentric Circles and a Sweeping Cone      85

Summary           91

6 The Power of Attached Properties 93

Overview of Attached Properties        93

Building the UseHover Attached Property     95

Using Attached Properties as Extension Points     100

Data Templates          102

Property Abstraction         102

Layout Animations          102

Constraining Panels         102

Application Services         102

UI Helper Objects         103

Implementing Drag and Drop with Attached Properties   103

Summary            111

Part II Adding Complex Features

7 Advanced Scrolling 113

The Anatomy of a Scrollbar         113

The Magic of IScrollInfo         115

Responding to User-Requested Horizontal and Vertical Scrolling 116

Controlling the Bounds for the Track and Thumb    116

Managing the Location of the Thumb      116

Logical Scrolling         117

Building a Custom Panel with Custom Scrolling     117

Creating the Layout Logic        117

Adding the Scrolling Functionality      119

Animated Scrolling          122

Taking Scrolling to the Next Step        123

Scrolling Without IScrollInfo        124

Summary            127

8 Virtualization 129

Virtualization Distilled         129

Building Blocks of UI Virtualization       130

UI Virtualization in WPF         131

Component Interaction         132

A Deeper Look at the ItemContainerGenerator    133

Making Our Own Virtualized Control: The StaggeredPanel  135

Deferred Scrolling          139

Container Recycling         140

Virtualization in 3D         140

Summary            142

9 Creating Advanced Controls and Visual Effects 143

Lasso Selection Using the InkCanvas       143

Building a Dock Slide Presenter       146

Docking and Undocking Controls       149

Building a Transition Abstraction: The TransitionContainer   154

Handling Transitions         157

Applying a Transition         159

Implementing Popular Visual Effects       161

Reflection           161

Drop Shadows          163

Opacity Masks          164

Gloss Effects           164

Summary            166

10 Control Skinning and Themes 167

Introduction to Skins and Themes       168

Resource Lookups in WPF        168

Building Default Styles        169

Using Resources in Default Styles        170

Creating Theme-Specific Styles        172

Enabling Runtime Skinning         174

Using the ApplyTemplate Override      177

Control Customization Through Property Exposure     182

Summary            183

PartIII BuildingInteractivity, 3D, Animations

11 Bridging the 2D and 3D Worlds 185

A Brief Introduction to 3D Worlds       185

Using the Viewport3D Element       186

Embedding a Viewport3D Element      189

Mapping 2D Visuals on 3D Surfaces       192

Getting Interactive with ModelUIElement3D and

ContainerUIElement3D        196

2D Bounds of a 3D Object        198

Hints on Layout in 3D        200

Interactive 2D-on-3D Surfaces        200

Summary            201

12 Custom Animations 203

Procedural Animations         203

Animating Using the DispatcherTimer      204

Animating Using CompositionTarget.Rendering     204

Animating with Storyboards        206

Simple Type-Based Animations (From, To, and By)    206

Keyframe Animations         207

Using Storyboards with Parallel Timelines      208

Using Path-Based Animations       211

Creating Custom Animations        212

Creating the 3D Surfaces         219

Animating Within the DrawingContext       220

Summary            221

13 Pixel Shader Effects 223

New and Improved Bitmap Effects       224

Working with Shaders          224

Setting Up the Environment       224

An Overview of HLSL         225

Writing Custom Shaders         228

Grayscale Shader         228

Building a Parameterized Shader: TwirlEffect     231

Animating the Shader Effects       235

Effect Mapping for GUI Interaction and Eventing    235

Multi-Input Shaders         239

A Useful Tool           242

Summary            242

Part IV Bringing the Controls to the Real World

14 Events, Commands, and Focus 243

Routed Events          243

Routed Events, Event Triggers, and Property Mirrors   245

Attached Events          246

Class Handlers          249

Weak Events Using Weak References       250

Implementing the Weak Event Pattern      251

Subclassing the Weak Event Manager      252

Delivering Events Via the IWeakEventListener     254

Commands           255

Routed Commands          259

Commands Versus Events        259

Request Requery         261

The ICommandSource Interface       262

Focus Management         266

Logical and Keyboard Focus        266

Focus-Related Events and Properties       267

Keyboard Navigation         271

Summary            273

15 Advanced Data Binding 275

Dependency Properties         276

Dependency Property Precedence       276

Using AddOwner Instead of Creating a New DependencyProperty  279

Listening to Property Changed Events on Dependency Properties  280

Special Data Binding Scenarios        282

Using RelativeSource.PreviousData      282

Using NotifyOnSourceUpdated and NotifyOnTargetUpdated   284

The Dispatcher and DispatcherPriority       285

Deferring UI Operations         287

Posting Messages from Worker Threads      287

The BackgroundWorker Class       289

Introduction to Continuous LINQ (CLINQ)     291

Summary            292

16 Control and Visual Design Tips 295

Control Design Tips         295

Use Internal Resource Dictionaries      295

Define Complex Controls as Partial Classes     296

Use Scoped Dependency Properties for Internal State Management  296

Use Attached Properties for Adding Functionality    297

Compose Graphics Using Simpler Building Blocks    297

Communicating Between a Control and Its Subparts   297

Use a State Machine to Handle Multiple Events and Property Changes         299

Use Low-Priority Delegates for Noncritical Tasks     299

Use x: Shared for Cloning Resources       299

Use Markup Extensions to Encapsulate Object Creation   300

Useful Patterns for GUI Development      301

The Strategy Pattern         301

The Builder Pattern         301

Model-View-Controller        302

Model-View-View Model         302

Factory Method          303

Composed Method          303

State Pattern           303

Code Should be Idiomatic with Regard to“Framework Design Guidelines”       304

Visual Design Tips          304

Using Tile Brushes          304

Using Gradients with Relative Transforms      306

XAML Coding Conventions        307

Use the Vista Interface Guidelines       308

Using Nonstandard Fonts for Icons      308

Using Transparent PNGs         309

Import from Photoshop and Illustrator      309

Opacity Masks          310

Using Clip Geometries        310

Some Useful Tools          312

Snoop            312

Mole           313

Kaxaml            313

Summary            315

17 Performance 317

Different Kinds of Performance       318

Choice of Visuals         318

Brushes and Caching         320

Resource Management        321

Reference Handling         321

Data Binding and Freezables       321

Background Threads for Long-Running Operations    322

Scrolling and Virtualization        322

Storyboard Animations        323

Pixel Shaders           323

Framework Property Metadata Options      323

RenderCapability–Hardware and Software Rendering    324

Optimizing the Render Pipeline       325

3D            325

Measuring Performance         326

Visual Profiler          327

Perforator           328

Third-Party Tools         329

Perceived Responsiveness        329

Summary            330

18 Control Automation 331

The Need for UI Automation        331

The Automation Object Model        332

Assemblies and Namespaces        333

AutomationElement, AutomationPeer, and Control Patterns   333

Automation Properties        335

Navigating the Automation Tree       336

Using the Automation API        338

Locating Elements in the Automation Tree      339

Checking for Control Patterns        340

Looking Up Property Values        341

Listening to Events          341

Navigating to the Parent, Child, or Sibling      342

Performing Operations on Automation Elements     342

Automation of a Custom Control        343

Picking a Base Peer Class         343

Picking Pattern Interfaces, aka the Control Patterns    344

Building RangeSelectorAutomationPeer      345

Additional Resources          349

Summary            349

Index            351