Hi Yuvraj,
1. Legend Items of the corresponding series will be removed only when the series is removed. But here we are just hiding the series.
However your requirement can be achieved by applying a custom DataTemplate to ItemsTemplate property of ChartLegend class. This is illustrated in the attached sample.
2. On setting the ShowGridLines property the axis is supposed to show the GridLines. In the attached sample you could see the GridLines visible for Primary Axis and invisible for Secondary Axis. Could you please check with the attached sample whether the code used in your side is proper.
I have modified the multiple axes sample and it is attached for your reference.
Please let us know if you have further queries.
Regards,
K. Saradha Devi.
MultipleAxes_WithLegendItemsRemoved_f0f8b5.zip