[SOLVED] Understanding TstringGrid behavior when adding a line to a sorted grid

[EganSolo]

  Context: TStringGrid sorted on a column.
  UseCase:
       1. Add a row
       2. Initialize Cell[SortedColumn,RowCount-1] to some value V.
       3. Call Cols[SortedColumn].IndexOf(V)
TStringGrid's Behavior:
1 => Appends a row to the bottom of the grid.
2 => Assigns the value to the cell
3 => Performs a binary search against the sort order of the column as it was before the new row was added. As a result, IndexOf might return -1 if the binary search misses V.

I don't have any issue with this behavior, but wanted to confirm that's what will happen in such a use case.
 

[EganSolo]

I've verified that the behavior listed below is correct. Appending to a sorted string grid disrupts the sort order, requiring you to resort again. In other words, when you sort the grid, it's a point-in-time operation that doesn't keep the grid sorted when you modify the rows (or columns) later. You must maintain the sort order in code by sorting the grid again.

[cdbc]

Hi

You must maintain the sort order in code by sorting the grid again

Hmmm... It works  ...but as you may know, QuickSort is not a 'stable' sort algorithm -- it may rearrange the items on every sort --
Thus, I've had better results with making a 'function AppendSorted()' and then either always use that or sort once & then /appendsorted/, that way you'll keep your items in place.
Regards Benny