Hard to tell what is happening unless you provide sample code.
Usually, if you are using data binding in WPF, you have implemented
public class ObservableCollection<T> : Collection<T>, INotifyCollectionChanged, INotifyPropertyChanged
If you are following the data binding requirements, then you may have a binding issue. The latest versions of Visual Studio have a XAML Binding Failures
Menu > Debug > Windows > XAML Binding Failures
A third possibility is that you are using public fields and not public properties. You can only data bind to properties, not fields.
If you are still having issues, please update your question and keep it simple and focused.