Data-Driven Services with Silverlight 2

Converters

When binding an entity object source to Silverlight 2 controls, it is often desirable to present the values in the target in a different format from the source. For example, when a date value is stored in a database, you almost always must format the value when you’re displaying it in a user interface. You might need to convert this value to an MM/DD/YYYY format to be displayed in a Silverlight user control. Another example might be a string property of an entity that represents a color, such as blue. You might intend to use this value as a Brush for a Silverlight 2 control. You must convert these types of values from their native format into a format that is appropriate. Type conversions are common and you can tackle them by creating a class that implements the IValueConverter interface.

IValueConverter

The IValueConverter interface exposes two methods that must be implemented. The Convert and ConvertBack methods handle converting a value to and from the target and source of a binding. The Convert method morphs the data on its way from the source to the target. The ConvertBack method morphs the data from the target and back to the source.

Using a converter requires the following steps. First, you must create a converter class that implements the IValueConverter interface. Next, you must implement both the Convert and ConvertBack methods. The Convert method converts the value from the source to the target. This conversion is required for all binding modes. The ConvertBack ...