I have a WPF/MVVM project that uses Xceed DataGridControl. Its ItemsSource is PagedCollectionView (Silverlight code). Now I do grouping by LastName field, and get grouped data in the grid - Smith's (5 rows), Johnson's (10 rows), Williams's (15 rows). Can the Xceed DataGridControl be templated in such manner, that upon some button click it would sort Johnson's records by FirstName field, leaving Smith's and Williams's - AND the global DataGrid 'LastName' column unsorted? Also, Johnson's rows must be displayed in same datagrid rows - if Johnson's group was occupying rows 6 to 16 - after applying such sort it should remain rows 6-16
There is nothing built-in for this specific behavior, but you could do it with some custom code. Something like a hidden column that would be used for the 'LastName' order, so you can use it to take precedence over the next column to sort.
To match your example, this CustomSortId could have a value of 1 for the Smith rows, 2 for the Johnson rows, and 3 for the Williams rows. You would then be able to sort by CustomSortId and then by FirstName to get the desired result.