Pro WPF in C# 2010: Windows Presentation Foundation in .NET 4

20.2. Data Conversion

In a basic binding, the information travels from the source to the target without any change. This seems logical, but it's not always the behavior you want. Often, your data source might use a low-level representation that you don't want to display directly in your user interface. For example, you might have numeric codes you want to replace with human-readable strings, numbers that need to be cut down to size, dates that need to be displayed in a long format, and so on. If so, you need a way to convert these values into the right display form. And if you're using a two-way binding, you also need to do the converse—take user-supplied data and convert it to a representation suitable for storage in the appropriate data object. ...