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- 1. WPF Data Binding Explained Peter Himschoot Trainer @ U2U Microsoft Regional Director Belux www.u2u.info/Blogs/Peter
- 2. Data Binding The need for data binding Using simple data binding Converting and validating data Using complex data binding Customizing data binding with templates Master-detail data binding Filtering, sorting and grouping data Xml, LINQ, ADO.NET data binding Debugging Data Binding
- 3. The need for Data Binding Imagine showing data retrieved from DB Move data from a column to a control Allow user to edit the data Validate the data Then move data from control to column Update the column Data Binding automates this!
- 4. What is Data Binding Control Property Object Property One Way Two Way
- 5. Simple Data Binding Bind one control’s property to one object’s data Control to control Control to (data) object
- 6. Data Conversion Bind to another type by converting it Add Converter class as a resource: Use Converter
- 7. Building a Converter Implement the IValueConverter interface
- 8. UpdateSourceTrigger TextBox doesn’t change value immediately To do so, set UpdateSourceTrigger UpdateSourceTrigger values: Default LostFocus (= Default for TextBox) PropertyChanged Explicit
- 9. Data Validation Users will always make mistakes Validation helps users determine these Default DataBinding doesn’t support this You need more verbose “Binding”
- 10. Exception Validation Data Source can throw Exception ExceptionValidationRule catches this
- 11. Custom Validation Rules Derive from ValidationRule
- 12. Using the ValidationRule Add it to the <ValidationRules> element
- 13. Custom Error Feedback Define a ControlTemplate resource
- 14. Using the ControlTemplate Set Validation.ErrorTemplate attached prop Validation will use this for feedback
- 15. Using Styles Even better, use a style for all textboxes
- 16. Using Tooltips User cannot see what is wrong Use a tooltip to show the actual error
- 17. Data Binding Multiple Properties Avoid repeating the same source Use DataContext!
- 18. Provide Data from Code May be easier to load data in codebehind Can set DataContext in code
- 19. Using Complex Data Binding Bind a control’s items to list of objects Objects are displayed using ToString()
- 20. Using Data Templates Display object with a DataTemplate Set control’s ItemTemplate DataTemplate DataSource = object
- 21. Selecting the DataTemplate By Name By Type Type selects DataTemplate
- 22. Dynamically Selecting a Template Use a DataTemplateSelector
- 24. Binding with DataProviders Use DataProvider in XAML Then set ItemsSource in XAML Your class or Service Proxy (Optional) Method to call
- 25. Asynchronous Data Binding Data Provider allows async binding Call method in background
- 26. Master Detail Binding Use ItemsControl (e.g. ListBox) as master Set IsSynchronizedWithCurrentItem="True" Other bindings on same source will follow master
- 27. Master Detail
- 28. DisplayMemberPath Replaces single-field template
- 29. Filtering with Views Use a CollectionView CollectionViewSource in XAML Implement the Filter event
- 30. Sorting and Grouping Again use a CollectionView
- 31. Sorting and Grouping Use a CollectionViewSource Define a GroupStyle
- 32. Binding to XML <XmlDataProvider x:Key="cars" XPath="/Cars/Car" Source="cars.xml" /> <TextBlock TextContent="{Binding XPath=@Make, Source={StaticResource cars}}" /> <Cars> <Car Make="Ford" Model="F-150"> <Image>truck.png</Image> </Car> <Car> ... </Car> </Cars> cars.xml
- 33. Provide XML from Code Can load XML data in codebehind Just like any other data XmlDocument doc = new XmlDocument(); doc.LoadXml("<Foo><Bar>Hello, world</Bar></Foo>"); myGrid.DataContext = doc;
- 34. Binding To DataSets Fill the DataSet as usual Then use it as the DataContext Controls use Path to reference Tables Columns
- 35. Dude, where’s the DataGrid? DataGrid like controls not provided Provided 3d party controls Infragistics Xceed …
- 36. Debugging Data Binding Binding failures generate debug messages Check the Output window in Visual Studio®