Three State Sorting
In the original grid, when clicking on a column header it will change sorting of the column starting from ascending to descending. Unfortunately you cannot get back to the original state(which is no sorting) without adding your own custom logic
for it. To get back to the original state you have to set the column.SortDirection back to null and clear out the SortDescriptions that were added when you click on the column header.Here when you use extended datagrid you don't have
to write any code for it.