Thanks for your reply. But in my case I donot want to select any row when grid is loaded for first time and shown to user. The user will select the row by clicking row indicator and at same time I also want user to select Cells. I am more interested in giving selectionunit = both i.e., when user clicks rowindicator entire row must be selected and rowindicator must move to that row and when user selects a cell only that cell must be selected not entire row. I was hoping you solved this issue.
Your pseudo code seems like to set the newly added row as the selecteditem.
The 'SelectionUnit' property can be set on the control itself (in the XAML file). Maybe that will solve your issue.
If that does not work, there are other events like 'SelectedCellsChanged' and 'SelectedCellsChanging'. You may want to try handling one of these events and setting the SelectionUnit in the handler for that.
My pseudocode showed solution for moving the row indicator to a newly added row only.