Charles Petzold Controls and Data Binding.

Charles Petzoldwww.charlespetzold.com

Controls and Data Binding

Agenda

• Built-in controls• Styles and templates• Data binding• Model-View-ViewModel (MVVM)• Items controls• The WebBrowser control• Application bars• Toolkit controls

• SWP contains assortment of basic controls– TextBox and PasswordBox– Button, CheckBox, RadioButton, and

HyperlinkButton– Slider and ProgressBar– MediaElement and MultiScaleImage– ListBox, Pivot, and Panorama– WebBrowser and other controls

• Touch support built in• More in Silverlight for Windows Phone

Toolkit

Controls

Button Control

<Button Width="400" Height="240" FontSize="{StaticResource PhoneFontSizeExtraLarge}" Content="Click Me" Click="OnClick" />

private void OnClick(object sender, RoutedEventArgs e){ ...}

Button with Custom Content

<Button Width="400" Height="240" Click="OnClick"> <Button.Background> <LinearGradientBrush StartPoint="0.5,0.0" EndPoint="0.5,1.0"> <GradientStop Offset="0.0" Color="#FF808080" /> <GradientStop Offset="1.0" Color="#FF202020" /> </LinearGradientBrush> </Button.Background> <Button.Content> <!-- Insert penguin XAML here --> </Button.Content></Button>

TextBox Control

// XAML<TextBox x:Name="Input" FontSize="36" />

// C#string input = Input.Text; // What the user typed

• SIP = Software Input Panel• InputScope property of text-input elements

permits SIP to be tailored to input type• More than 60 input scopes available

SIPs and Input Scopes

InputScope="Default"

InputScope="TelephoneNumber"

Specifying an Input Scope

// Short form (XAML)<TextBox x:Name="Input" InputScope="TelephoneNumber" />

// Long form (XAML with IntelliSense)<TextBox x:Name="Input"> <TextBox.InputScope> <InputScope> <InputScopeName NameValue="TelephoneNumber" /> </InputScope> </TextBox.InputScope></TextBox>

// C#Input.InputScope = new InputScope() { Names = { new InputScopeName() { NameValue = "TelephoneNumber" } } };

Useful Input Scopes

Name Description

Default Basic text entry (letters, numbers, and symbols)

Text Text entry with auto-capitalization, auto-complete, and more

Number Numeric data entry

TelephoneNumber Phone number data entry

EmailSmtpAddress E-mail address data entry

Url URL data entry

ProgressBar Control

<!-- ProgressBar with default min and max (0 and 100) --><ProgressBar Value="40" />

<!-- ProgressBar with custom min and max --><ProgressBar Minimum="1" Maximum="1000" />

<!-- Indeterminant ProgressBar --><ProgressBar IsIndeterminant="true" />

ProgressBar showing 40% complete Indeterminant ProgressBar

ProgressBar Performance

// Never do this!<ProgressBar x:Name="Progress" IsIndeterminant="true" />

// Do this instead<ProgressBar x:Name="Progress" /> ...Progress.IsIndeterminant = true; // Operation begins ...Progress.IsIndeterminant = false; // Operation completes

demoControl Basics

• Allow look and feel to be factored from content– Provide level of indirection between visual

properties and their values• Style = Collection of property values

– Define style as XAML resource– Apply style using {StaticResource} markup

extension– Or apply it programmatically

• Global scope or local scope

Styles

Defining a Global Style

// App.xaml<Application.Resources> <Style x:Key="ButtonStyle" TargetType="Button"> <Setter Property="Width" Value="400" /> <Setter Property="Height" Value="240" /> </Style></Application.Resources>

Defining a Local Style

// MainPage.xaml<Grid.Resources> <Style x:Key="ButtonStyle" TargetType="Button"> <Setter Property="Width" Value="400" /> <Setter Property="Height" Value="240" /> </Style></Grid.Resources>

Applying Styles

<Button Style="{StaticResource ButtonStyle}" ... /><Button Style="{StaticResource ButtonStyle}" ... /><Button Style="{StaticResource ButtonStyle}" ... /><Button Style="{StaticResource ButtonStyle}" Width="100" ... />

Explicit property value overrides style property value

<Style x:Key="ButtonStyle" TargetType="Button"> <Setter Property="Width" Value="400" /> <Setter Property="Height" Value="240" /></Style>

<Style x:Key="TranslucentButtonStyle" TargetType="Button" BasedOn="{StaticResource ButtonStyle}"> <Setter Property="Opacity" Value="0.5" /></Style>

BasedOn Styles

demoStyles

• Redefine a control’s entire visual tree– Perform deep customization while retaining

basic behavior of control– Exposed through control's Template property

• Inherited from Control base class• Use {TemplateBinding} to flow property

values from control to template• Use ContentPresenter and ItemsPresenter to

flow content and items to template

Control Templates

Elliptical Button

<Button Foreground="Black"> <Button.Template> <ControlTemplate TargetType="Button"> <Grid> <Ellipse Width="256" Height="128"> <Ellipse.Fill> <RadialGradientBrush GradientOrigin="0.25,0.25"> <GradientStop Offset="0.25" Color="White" /> <GradientStop Offset="1.0" Color="Red" /> </RadialGradientBrush> </Ellipse.Fill> </Ellipse> <TextBlock FontSize="24" Text="Click Me" HorizontalAlignment="Center" VerticalAlignment="Center" /> </Grid> </ControlTemplate> </Button.Template></Button>

<Button Width="256" Height="128" FontSize="24" Content="Click Me" Foreground="Black"> <Button.Template> <ControlTemplate TargetType="Button"> <Grid> <Ellipse Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"> <Ellipse.Fill> <RadialGradientBrush GradientOrigin="0.25,0.25"> <GradientStop Offset="0.25" Color="White" /> <GradientStop Offset="1.0" Color="Red" /> </RadialGradientBrush> </Ellipse.Fill> </Ellipse> <TextBlock FontSize="24" Text="{TemplateBinding Content}" HorizontalAlignment="Center" VerticalAlignment="Center" /> </Grid> </ControlTemplate> </Button.Template></Button>

{TemplateBinding}

<Button Width="256" Height="128" FontSize="24" Content="Click Me" Foreground="Black"> <Button.Template> <ControlTemplate TargetType="Button"> <Grid> <Ellipse Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"> <Ellipse.Fill> <RadialGradientBrush GradientOrigin="0.25,0.25"> <GradientStop Offset="0.25" Color="White" /> <GradientStop Offset="1.0" Color="Red" /> </RadialGradientBrush> </Ellipse.Fill> </Ellipse> <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" /> </Grid> </ControlTemplate> </Button.Template></Button>

ContentPresenter

Combining Styles and Templates

<Style x:Key="EllipticalButton" TargetType="Button"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="Button"> <Grid> <Ellipse Width="{TemplateBinding Width}" Height="{TemplateBinding Height}"> <Ellipse.Fill> <RadialGradientBrush GradientOrigin="0.25,0.25"> <GradientStop Offset="0.25" Color="White" /> <GradientStop Offset="1.0" Color="Red" /> </RadialGradientBrush> </Ellipse.Fill> </Ellipse> <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" /> </Grid> </ControlTemplate> </Setter.Value> </Setter></Style>

demoControl Templates

• Permits properties of one object to be bound to properties of another– Target property must be DependencyProperty– Source property can be any type of property– Source can be a collection if target is items

control• OneTime, OneWay, and TwoWay bindings• {Binding} markup extension provides

declarative support for data binding

Data Binding

Data Binding Schema

ValueConverter

Target

DependencyProperty

BindingObject

Source

Property

Converts data format and optionally validates it in two-way data binding scenarios

Provides data and optionally receives it (two-way binding)

Consumes data and optionally sends it (two-way binding)

Flows data between source and target

• Creates Binding objects declaratively

{Binding}

<TextBox x:Name="Input" FontSize="36" /><TextBlock x:Name="Output" Text="{Binding Text}" FontSize="36" />

TextBlock

TextProperty

BindingObject

TextBox

TextProperty

Specifying the Data Source (1)// XAML<TextBox x:Name="Input" FontSize="36" /><TextBlock x:Name="Output" Text="{Binding Text}" FontSize="36" />

// C#Output.DataContext = Input;

Specifying the Data Source (2)<TextBox x:Name="Input" Height="24" FontSize="36" /><TextBlock x:Name="Output" FontSize="36" Text="{Binding Text, ElementName=Input}" />

ElementName identifies another XAML element as the data source

Two-Way Data Binding

<TextBox x:Name="Input" Text="40" FontSize="36" /><Slider Minimum="0" Maximum="100" Value="{Binding Text, ElementName=Input, Mode=TwoWay}" />

Mode identifies the binding mode

• Infrastructural interface used in data classes

• Notifies binding object when data changes• Essential for one-way data binding!

INotifyPropertyChanged

Data Class

Property

Property

Property

INotifyPropertyChanged

Implementing INotifyPropertyChangedpublic class Person : INotifyPropertyChanged{ public event PropertyChangedEventHandler PropertyChanged; private decimal _salary; public decimal Salary { get { return _salary; } set { _salary = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Salary")); } }}

• Infrastructural interface used in collection classes

• Notifies binding object when collection changes

INotifyCollectionChanged

Collection Class

Item

Item

Item

INotifyCollectionChanged

IList

ICollection

IEnumerable

• BCL collection class that implements INotifyCollectionChanged– System.Collections.ObjectModel namespace

• Fires CollectionChanged events when items are added or removed (or collection is refreshed)

ObservableCollection

// Ordinary collectionList<string> names = new List<string>();

// Observable collectionObservableCollection<string> names = new ObservableCollection<string>();

• Objects that convert values involved in data binding from one type to another

• Implement IValueConverter– Convert – Convert from type A to type B– ConvertBack – Convert from type B to type A

• Specified with Converter attribute in {Binding} expression

Value Converters

ImageConverter

public class ImageConverter : IValueConverter{ public object Convert(object value, Type targetType,        object parameter, CultureInfo culture) { BitmapImage bi = new BitmapImage(); bi.SetSource(new MemoryStream((Byte[])value)); return bi; }  public object ConvertBack(object value, Type targetType,        object parameter, CultureInfo culture) { throw new NotImplementedException(); }}

Using ImageConverter

<Grid.Resources> <local:ImageConverter x:Key="ImageConverter" /></Grid.Resources> . . .<DataTemplate> <Image Source="{Binding ThumbnailImage, Converter={StaticResource ImageConverter}}" /></DataTemplate>

demoData Binding

• Controls that display collections of items• Generally acquire items through data

binding• Data templates control how items are

rendered

Items Controls

PivotListBox Panorama

ListBox Control

// XAML<ListBox FontSize="{StaticResource PhoneFontSizeExtraLarge}" SelectionChanged="OnSelectionChanged"> <ListBoxItem Content="Item One" /> <ListBoxItem Content="Item Two" /> <ListBoxItem Content="Item Three" /></ListBox>

// C#private void OnSelectionChanged(object sender, SelectionChangedEventArgs e){ int index = (sender as ListBox).SelectedIndex; ...}

ListBox with Rich Content

<ListBox> <StackPanel Orientation="Horizontal"> <Image Source="Item.png" Margin="8" /> <StackPanel Orientation="Vertical"> <TextBlock Text="Item One" Style="{StaticResource PhoneTextExtraLargeStyle}" /> <TextBlock Text="Convallis dapibus non ut justo" Style="{StaticResource PhoneTextAccentStyle}" /> </StackPanel> </StackPanel> . . .</ListBox>

ListBox Data Binding

// XAML<ListBox x:Name="List" FontSize="{StaticResource PhoneFontSizeExtraLarge}" />

// C#string[] items = { "Item One", "Item Two", "Item Three"};

List.ItemsSource = items;

ListBox Data Templates

<ListBox x:Name="List"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <Image Source="{Binding Source}" Margin="8" /> <StackPanel Orientation="Vertical"> <TextBlock Text="{Binding Title}" Style="..." /> <TextBlock Text="{Binding Description}" Style="..." /> </StackPanel> </StackPanel> </DataTemplate> </ListBox.ItemTemplate></ListBox>

Providing a Data Source

ObservableCollection<Item> items = new ObservableCollection<Item>();items.Add(new Item { Source = "Item.png", Title = "Item One", Description = "Convallis dapibus non ut justo" });items.Add(new Item { Source = "Item.png", Title = "Item Two", Description = "Convallis dapibus non ut justo" });items.Add(new Item { Source = "Item.png", Title = "Item Three", Description = "Convallis dapibus non ut justo" });List.ItemsSource = items;

public class Item{ public string Source { get; set; } public string Title { get; set; } public string Description { get; set; }}

• SelectedIndex gets and sets index of selected item– -1 means no item is currently selected

• SelectedItem property gets reference to item that is currently selected – with strong typing– null means no item is currently selected

The SelectedItem Property

// SelectedItem returns an Item reference because ListBox// is bound to collection of Item objectsItem item = List.SelectedItem as Item;String title = item.Title; // e.g., "Item One"

• Model-View-ViewModel• Popular design pattern used by teams doing

WPF, Silverlight, and phone development– Loose coupling; separation of concerns– Enhanced testability and "Blendability"– Based on Martin Fowler's Presentation Model

pattern• Devised in 2005 by Microsoft's John

Gossman• WP7 lacks rich MVVM support

(commanding)

MVVM

Model-View-ViewModel

Model ViewModel View

Control

ControlProperty

PropertyModelClass

ModelClass

ModelClass

Data

Bin

din

g

ViewModel Example

public class ViewModel{ public ObservableCollection<Item> Items { get; set; }

public ViewModel() { Items = new ObservableCollection<Item>(); Items.Add(new Item { Source = "Item.png", Title = "Item One", Description = "..." }); Items.Add(new Item { Source = "Item.png", Title = "Item Two", Description = "..." }); Items.Add(new Item { Source = "Item.png", Title = "Item Three", Description = "..." }); }}

Binding to a ViewModel

<Grid ...> <Grid.Resources> <local:ViewModel x:Key="ItemsViewModel" /> </Grid.Resources> <ListBox x:Name="List" ItemsSource="{Binding Items}" DataContext="{StaticResource ItemsViewModel}"> <ListBox.ItemTemplate> <DataTemplate> ... </DataTemplate> </ListBox.ItemTemplate> </ListBox></Grid>

demoListBoxes, Data Binding, and MVVM

Pivot Control

• Functionally similar to Tab control• Divides a page into navigable items

(PivotItems)• Implemented in Microsoft.Phone.Controls.dll

Declaring a Pivot Control

<controls:Pivot x:Name="PivotControl" Title="GEEK FEED"> <controls:PivotItem Header="abc"> <!-- Declare PivotItem content here --> </controls:PivotItem> <controls:PivotItem Header="bbc"> <!-- Declare PivotItem content here --> </controls:PivotItem> <controls:PivotItem Header="wired"> <!-- Declare PivotItem content here --> </controls:PivotItem></controls:Pivot>

• Gets and sets index of current PivotItem• Can't be set until control fires Loaded event

if control contains more than three PivotItems

The SelectedIndex Property

// Get SelectedIndex (works anywhere)int index = PivotControl.SelectedIndex;

// Set SelectedIndex (works reliably only after Loaded event)PivotControl.SelectedIndex = 3;

demoPivot Control

Panorama Control

• Divides page into navigable PanoramaItems• Supports image background for magazine

feel• Implemented in Microsoft.Phone.Controls.dll

Declaring a Panorama Control

<controls:Panorama x:Name="PanoramaControl" Title="pictures"> <controls:Panorama.Background> <ImageBrush ImageSource="PanoramaBackground.png"/> </controls:Panorama.Background> <controls:PanoramaItem Header="gallery"> <!-- Declare PanoramaItem content here --> </controls:PanoramaItem> <controls:PanoramaItem Header="recent"> <!-- Declare PanoramaItem content here --> </controls:PanoramaItem> <controls:PanoramaItem Header="samples"> <!-- Declare PanoramaItem content here --> </controls:PanoramaItem></controls:Panorama>

• Panorama's SelectedIndex property is read-only

• Set SelectedIndex indirectly by setting DefaultItem

The DefaultItem Property

// Get SelectedIndexint index = PanoramaControl.SelectedIndex;

// Force SelectedIndex by setting DefaultItemPanoramaControl.DefaultItem = PanoramaControl.Items[3];

demoPanorama Control

• Displays live HTML content from URI or string– Source property downloads content– NavigateToString method injects content– IsScriptEnabled property controls script support

• Defaults to false; set to true to enable script• InvokeScript method and ScriptNotify event

facilitate communication between app and script

• Supports isolated storage as source of content– With support for relative URIs

WebBrowser Control

Displaying Remote Content

<phone:WebBrowser Source="http://www.bing.com" IsScriptEnabled="true" />

Inserting Content

// XAML<phone:WebBrowser x:Name="Browser" Loaded="OnWebBrowserLoaded" />

// C#private void OnWebBrowserLoaded(object sender, RoutedEventArgs e){ Browser.NavigateToString("<h1>Hello, phone</h1>");}

• Add pages to project– Set build action to Content– URIs inside must be absolute

• Load pages with XNA's TitleContainer.OpenStream– Microsoft.Xna.Framework

assembly• Read content with

StreamReader• Pass content to WebBrowser

control with NavigateToString

Loading Local Pages

local.html

<html><body style="background: black"><img src="http://www.wintellect.com/images/WintellectLogo.png" /></body></html>

URI must be absolute since origin is undefined

Loading local.html

// XAML<phone:WebBrowser x:Name="Browser" Loaded="OnWebBrowserLoaded" />

// C#private void OnWebBrowserLoaded(object sender, RoutedEventArgs e){ StreamReader reader = new StreamReader(TitleContainer.OpenStream("local.html")); Browser.NavigateToString(reader.ReadToEnd());}

• For local pages with relative links, store pages and resources they reference in isolated storage– Store entire sites on the phone– One usage scenario: HTML-based help systems

• Optionally use WebBrowser.Base property to specify base folder for relative links

• App must write pages to isolated storage– No tooling to help out

WebBrowser and Isolated Storage

Isolated Storage

Using Isolated Storage

<phone:WebBrowser Base="Help" Source="Page1.html" />

HelpMain

Page1.html

Page2.html

Styles.css

Pages can contain relative links to each other and to other resources

Application

Relative URI refers to resource in isolated storage

• Invokes script functions in WebBrowser control– Don't forget IsScriptEnabled="true"

• Calls are synchronous

WebBrowser.InvokeScript

// C#string result = Browser.InvokeScript("toUpper", "Hello, phone").ToString();

// JavaScriptfunction toUpper(text) { return text.toUpperCase(); // Returns "HELLO, PHONE"}

• Event fired by WebBrowser control when script inside it calls window.external.notify

WebBrowser.ScriptNotify

// JavaScriptwindow.external.notify('Ready');

// C#private void OnScriptNotify(object sender, NotifyEventArgs e){ MessageBox.Show(e.Value); // e.Value == "Ready"}

demoWebBrowser Control

Application Bars

• Quick, easy access to common tasks– Up to four buttons with hints/labels– Up to five menu items

• "Use icon buttons for the primary, most-used actions in the application. Do not use four icons just to use them. Less is more in this space."

Declaring an Application Bar

<phone:PhoneApplicationPage.ApplicationBar> <shell:ApplicationBar IsVisible="True"> <shell:ApplicationBarIconButton IconUri="/Icons/appbar.refresh.rest.png" Text="Refresh" Click="OnRefreshButtonClicked" /> <shell:ApplicationBarIconButton IconUri="/Icons/appbar.settings.rest.png" Text="Settings" Click="OnSettingsButtonClicked" /> </shell:ApplicationBar></phone:PhoneApplicationPage.ApplicationBar>

Processing Button Clicks

void OnRefreshButtonClicked(object sender, EventArgs e){ // TODO: Respond to Refresh button}

void OnSettingsButtonClicked(object sender, EventArgs e){ // TODO: Respond to Settings button}

Disabling Buttons in Code

// XAML<shell:ApplicationBarIconButton x:Name="RefreshButton" IconUri="/Icons/appbar.refresh.rest.png" Text="Refresh" Click="OnRefreshButtonClicked" />

// This throws a NullReferenceExceptionRefreshButton.IsEnabled = false;

// This doesn't(ApplicationBar.Buttons[0] as ApplicationBarIconButton).IsEnabled = false;

Application Bar Icons

• 32 stock icons provided in WP7 SDK– \Program Files\Microsoft SDKs\Windows Phone\

v7.0\Icons\dark• Use "dark" icons only in application bars• Set Build Action to "Content" in Visual

Studio

Refresh New Delete Save

Play Pause Settings Download

Custom Application Bar Icons

• Icon must be 48 x 48 pixels• Icon must have a transparent background• Icon foreground must be white

– Allows OS to colorize based on selected theme• http://www.kirupa.com/windowsphone/

creating_custom_applicationbar_icon.htm

demoApplication Bars

• Silverlight for Windows Phone Toolkit contains additional controls– Source code– Binaries– Samples

• http://silverlight.codeplex.-com/releases/view/55034

Toolkit Controls

Using the ToggleSwitch Control// XAML<toolkit:ToggleSwitch Header="Wi Fi networking" Click="OnClick" />

// C#private void OnClick(object sender, RoutedEventArgs e){ if ((bool)(sender as ToggleSwitch).IsChecked) MessageBox.Show("On"); else MessageBox.Show("Off");}

Using the DatePicker Control

// XAML<toolkit:DatePicker ValueChanged="OnValueChanged" />

// C#private void OnValueChanged(object sender, DateTimeValueChangedEventArgs e){ MessageBox.Show(e.NewDateTime.ToString());}

You provide these icons; DatePicker provides the application bar and buttons

Charles Petzoldwww.charlespetzold.com

Questions?