Vista - Databinding issue

Hi
I am using a XmlDataProvider to bind my Controls. I recieve XML Data
from a port.I want to refresh the view everytime i get new data.How
can i do this?
My code goes as below.

public Template1()
{
InitializeComponent();
realTimeDataListner = new RealTimeDataListener();
realTimeDataListner.DataFetchCompleted += new
EventHandler<DataFetchCompletedEventArgs>(realTimeDataListner_DataFetchCompleted);
realTimeDataListner.GetDataAsync();

}

void realTimeDataListner_DataFetchCompleted(object sender,
DataFetchCompletedEventArgs e)
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(e.Data);
XmlDataProvider xmlDataProvider =
(XmlDataProvider)this.FindResource("xmlSource");
xmlDataProvider.Document = xmlDoc;
realTimeDataListner.GetDataAsync();

}

The DataFetchCompleted event gets fired everytime I get new data but
setting the xmlDataProvider.Document = xmlDoc does not reflect any
change.How do I notify my UI about the change?