c# - Object does not match target type with WinRT XAML Toolkit Chart -

As mentioned in the title, when I WinRT XAML Toolkit 's chart

This is a quick snippet of my code:

  public observableDictionary & lt; String, int & gt; MyDict {Receive; Set; } ... & lt; Charting: Chart grid. Line = "2" margin = "0" & ​​gt; & Lt; Charting: Chart.Series & gt; & Lt; Charting: Line Series Items Source = "{Binding MyDict}" Independent Value Binding = "{Binding Key}" Dependency = Bearing = "{Binding Value}" /> & Lt; / Charting: Chart.Series & gt; & Lt; / Charting: Chart & gt;  

I can not find some useful online and I really do not want to be compelled to write a new class which is a list because it is very nonsense .

Any thoughts?