This is useful for controls such as Check Boxes, where the update should happen when the control is clicked, not when it loses focus. UI virtualization occurs when a subset of user interface (UI) elements are generated from a larger number of data items based on which items are visible on the screen.
This enables you to use a background thread to receive data from an external source, such as a database, and display the data on the UI thread.
By using another thread to modify the collection, your user interface remains responsive to user interaction.
If you run the program you will see that the first text box has already read the value from the source. When the control loses focus, the Text Block at the bottom of the window updates, showing that the information entered is copied back to the source.
Next, let's change the second text box so that it uses one way binding.
When an Items Control is data bound to a collection, an item container is generated for each item.
In some cases, item containers are removed from the visual tree.The INotify Data Error Info interface enables data entity classes to implement custom validation rules and expose validation results asynchronously. In this example, when the user moves the Slider, the source updates for each pixel that the Slider moves.This interface also supports custom error objects, multiple errors per property, cross-property errors, and entity-level errors. The source object typically needs the value of the slider only when the slider's In certain cases, you might get the Binding Expression of a Binding and need information about the source and target objects of the binding.WPF 4.5 enables the data to be rearranged when the data is modified.For example, suppose that an application uses a Data Grid to list stocks in a stock market and the stocks are sorted by stock value.The ninety-fourth part of the Windows Presentation Foundation Fundamentals tutorial adds to the description of data binding.