As long as the Pair is a class and not a struct it should be possible to use only XAML. However, I am unsure how you need to chart the data. I am unsure about the TimeSpan part. You can use two linear axes and a scatter series (ScatterLineSeries or else). You can then set the XValueBinding of the series to the TotalHours of the time span and the YValueBinding to the double property. But the chart will display the total hours in the X-axis labels and I am not sure what this will mean to your users. However, you can give it a try. If you need further assistance I will ask that you provide us with a snapshot (drawing of some sort) that depicts the output you are after.
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