Data-Driven Services with Silverlight 2

DataContext

Up to this point, I have alluded to the DataContext property but haven’t discussed it in depth. It is time to give it some attention by examining where it is used, what it does, and how it can benefit a Silverlight application.

The DataContext property refers to a source of data that you can bind to a target. The DataContext often is set to an instance of an entity, such as a Person in the previous examples. Once you set the DataContext, you can bind it to any controls that have access to it. For instance, you can use it to bind all controls within a container control to a single data source. This approach is useful when several controls use the same binding source. It could become repetitive to indicate the binding source for every control. Instead, you can set the DataContext for the container of the controls.

Each FrameworkElement has a DataContext. This includes the instances of the UserControl class that the examples in this chapter have demonstrated, as the UserControl class inherits from the Control class, which in turn inherits from the FrameworkElement class. This means that on a single UserControl, objects could be assigned to dozens of DataContext properties of various FrameworkElement controls. For example, the UserControl, a layout control such as a Grid, and a series of interactive controls such as TextBoxes, CheckBoxes, and ListBoxes might all have their DataContext property set.

DataContext and Source

You can assign the binding source via the Source property ...