AzureStorageAnalyticsViewer.TimelineChart.AddSeries C# (CSharp) Method

        public void AddSeries(string propname)
        {
            var mi = contextmenu1.Items.Cast<MenuItem>().First(i => propname.CompareTo(i.Header) == 0);
            if (!mi.IsChecked)
                mi.IsChecked = true;
        }
        void item_Checked(object sender, RoutedEventArgs e)