WPF Toolkit Pie Chart Fill Values

I Fill my Pie Chart with Data (form observablehas -> dict) but everytime the chart gets new data, the pie fades out and fades i开发者_开发技巧n. I want the pie slices to change like here: http://silverlight.net/content/samples/sl2/toolkitcontrolsamples/run/default.html

if you choose "Pie Series" and then look at "dynamic data items".

When you get new data, you should add them to the ObservableCollection without clearing the ObservableCollection first. I assume you either overwrite your ObservableCollection or you clear it before adding the new data.