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Satisfy Your Technical Curiosity

WPF Data BindingWPF Data BindingExplainedExplainedPeter HimschootPeter HimschootTrainer @ U2UTrainer @ U2U

Microsoft Regional Director BeluxMicrosoft Regional Director Beluxwww.u2u.info/Blogs/Peterwww.u2u.info/Blogs/Peter

Satisfy Your Technical CuriositySatisfy Your Technical Curiosity

Data BindingData Binding

The need for data bindingThe need for data bindingUsing simple data bindingUsing simple data bindingConverting and validating dataConverting and validating dataUsing complex data bindingUsing complex data bindingCustomizing data binding with templatesCustomizing data binding with templatesMaster-detail data bindingMaster-detail data bindingFiltering, sorting and grouping dataFiltering, sorting and grouping dataXml, LINQ, ADO.NET data bindingXml, LINQ, ADO.NET data bindingDebugging Data BindingDebugging Data Binding

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The need for Data BindingThe need for Data Binding

Imagine showing data retrieved from DBImagine showing data retrieved from DBMove data from a column to a controlMove data from a column to a controlAllow user to edit the dataAllow user to edit the dataValidate the dataValidate the dataThen move data from control to columnThen move data from control to columnUpdate the columnUpdate the column

Data Binding automates this!Data Binding automates this!


What is Data BindingWhat is Data Binding4

Control

Property

Object

Property

One WayTwo Way


Simple Data BindingSimple Data Binding

Bind one control’s property to one object’s dataBind one control’s property to one object’s dataControl to controlControl to control

Control to (data) objectControl to (data) object

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Data ConversionData Conversion

Bind to another type by converting itBind to another type by converting itAdd Converter class as a resource:Add Converter class as a resource:

Use ConverterUse Converter

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Building a ConverterBuilding a Converter

Implement the IValueConverter interfaceImplement the IValueConverter interface

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UpdateSourceTriggerUpdateSourceTrigger

TextBox doesn’t change value immediatelyTextBox doesn’t change value immediatelyTo do so, set UpdateSourceTriggerTo do so, set UpdateSourceTrigger

UpdateSourceTrigger values:UpdateSourceTrigger values:DefaultDefaultLostFocus (= Default for TextBox)LostFocus (= Default for TextBox)PropertyChangedPropertyChangedExplicitExplicit

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Data ValidationData Validation

Users will always make mistakesUsers will always make mistakesValidation helps users determine theseValidation helps users determine theseDefault DataBinding doesn’t support thisDefault DataBinding doesn’t support this

You need more verbose “Binding”You need more verbose “Binding”

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Exception ValidationException Validation

Data Source can throw ExceptionData Source can throw Exception

ExceptionValidationRule catches thisExceptionValidationRule catches this

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Custom Validation RulesCustom Validation Rules

Derive from ValidationRuleDerive from ValidationRule

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Using the ValidationRuleUsing the ValidationRule

Add it to the <ValidationRules> elementAdd it to the <ValidationRules> element

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Custom Error FeedbackCustom Error Feedback

Define a ControlTemplate resourceDefine a ControlTemplate resource

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Using the ControlTemplateUsing the ControlTemplate

Set Validation.ErrorTemplate attached propSet Validation.ErrorTemplate attached prop

Validation will use this for feedbackValidation will use this for feedback

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Using StylesUsing Styles

Even better, use a style for all textboxesEven better, use a style for all textboxes

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Using TooltipsUsing Tooltips

User cannot see what is wrongUser cannot see what is wrongUse a tooltip to show the actual errorUse a tooltip to show the actual error

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Data Binding Multiple PropertiesData Binding Multiple Properties

Avoid repeating the same sourceAvoid repeating the same source

Use DataContext!Use DataContext!

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Provide Data from CodeProvide Data from Code

May be easier to load data in codebehindMay be easier to load data in codebehindCan set DataContext in codeCan set DataContext in code

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Using Complex Data BindingUsing Complex Data Binding

Bind a control’s items to list of objectsBind a control’s items to list of objects

Objects are displayed using ToString()Objects are displayed using ToString()

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Using Data TemplatesUsing Data TemplatesDisplay object with a DataTemplateDisplay object with a DataTemplate

Set control’s ItemTemplateSet control’s ItemTemplate

DataTemplate DataSource = objectDataTemplate DataSource = object

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Selecting the DataTemplateSelecting the DataTemplate

By NameBy Name

By TypeBy Type

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Type selectsDataTemplate


Dynamically Selecting a TemplateDynamically Selecting a Template

Use a DataTemplateSelectorUse a DataTemplateSelector

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PersonDataTemplateSelectorPersonDataTemplateSelector23


Binding with DataProvidersBinding with DataProviders

Use DataProvider in XAMLUse DataProvider in XAML

Then set ItemsSource in XAMLThen set ItemsSource in XAML

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Your class orService Proxy

(Optional)Method to call


Asynchronous Data BindingAsynchronous Data Binding

Data Provider allows async bindingData Provider allows async bindingCall method in backgroundCall method in background

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Master Detail BindingMaster Detail Binding

Use ItemsControl (e.g. ListBox) as masterUse ItemsControl (e.g. ListBox) as masterSet IsSynchronizedWithCurrentItem="True"Set IsSynchronizedWithCurrentItem="True"

Other bindings on same source will follow Other bindings on same source will follow mastermaster

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Master Detail Master Detail 27


DisplayMemberPathDisplayMemberPath

Replaces single-field templateReplaces single-field template

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Filtering with ViewsFiltering with Views

Use a CollectionViewUse a CollectionViewCollectionViewSource in XAMLCollectionViewSource in XAML

Implement the Filter eventImplement the Filter event

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Sorting and GroupingSorting and Grouping

Again use a CollectionViewAgain use a CollectionView

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Sorting and GroupingSorting and Grouping

Use a CollectionViewSourceUse a CollectionViewSource

Define a GroupStyleDefine a GroupStyle

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Binding to XMLBinding to XML

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<Cars> <Car Make="Ford" Model="F-150"> <Image>truck.png</Image> </Car> <Car> ... </Car></Cars>

cars.xml

<XmlDataProvider x:Key="cars" XPath="/Cars/Car" Source="cars.xml" />

<TextBlock TextContent="{Binding XPath=@Make, Source={StaticResource cars}}"/>


Provide XML from CodeProvide XML from Code

Can load XML data in codebehindCan load XML data in codebehindJust like any other dataJust like any other data

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XmlDocument doc = new XmlDocument();doc.LoadXml("<Foo><Bar>Hello, world</Bar></Foo>");

myGrid.DataContext = doc;


Binding To DataSetsBinding To DataSets

Fill the DataSet as usualFill the DataSet as usualThen use it as the DataContextThen use it as the DataContext

Controls use Path to referenceControls use Path to referenceTablesTables

ColumnsColumns

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Dude, where’s the DataGrid?Dude, where’s the DataGrid?

DataGrid like controls not providedDataGrid like controls not providedProvided 3d party controlsProvided 3d party controls

InfragisticsInfragisticsXceedXceed……


Debugging Data BindingDebugging Data Binding

Binding failures generate debug messagesBinding failures generate debug messages

Check the Output window in Visual Studio®Check the Output window in Visual Studio®

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data binding binding

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