how to redo or undo in fpspreadsheet [done with snippet]

[Mongkey]

is there anyone here could do redo or undo under fpspreadsheet worksheetgrid editor?

Thank you.

[Xenno]

The simplest way would be saving the sheet to (temporary) files before any action. Keep the file names in a LIFO list (stack). Just load the file in reverse order to Undo or the opposite to Redo. These snapshot files must be removed when no longer needed. To save space, you may use compression with a little consequences.

[Mongkey]

thank you bro,
I got vision from gr*k, this code fully worked:

Code: Pascal  [Select][+][-]

1. type
2.   TCellEdit_ = record
3.     Row, Col: integer;
4.     OldValue, NewValue: variant;
5.   end;
6.  
7.   TUndoRedoList = array of TCellEdit_;
8.  
9. var
10.   UndoStack, RedoStack: array of TUndoRedoList;
11.  
12.   OldCellValue, NewCellValue: variant;
13.  
14. procedure Undo;
15. var
16.   LastActions: TUndoRedoList;
17.   Act: TCellEdit_;
18.   i: integer;
19. begin
20.   if Length(UndoStack) = 0 then Exit;
21.  
22.   // Pop the last group of actions
23.   LastActions := UndoStack[High(UndoStack)];
24.   SetLength(UndoStack, Length(UndoStack) - 1);
25.  
26.   // Push the whole group to Redo stack (important for batch undo)
27.   SetLength(RedoStack, Length(RedoStack) + 1);
28.   RedoStack[High(RedoStack)] := LastActions;
29.  
30.   // Revert all actions in the group
31.   for i := 0 to High(LastActions) do
32.   begin
33.     Act := LastActions[i];
34.     Form1.WorksheetGrid.Cells[Act.Col, Act.Row] := Act.OldValue;
35.   end;
36.  
37.   // Optional: if you want the edit box to show the current (now old) value
38.   if Length(LastActions) > 0 then
39.   begin
40.     Act := LastActions[High(LastActions)]; // last edited cell
41.   end;
42. end;
43.  
44. procedure Redo;
45. var
46.   LastActions: TUndoRedoList;
47.   Act: TCellEdit_;
48.   i: integer;
49. begin
50.   if Length(RedoStack) = 0 then Exit;
51.  
52.   // Pop the last group from redo
53.   LastActions := RedoStack[High(RedoStack)];
54.   SetLength(RedoStack, Length(RedoStack) - 1);
55.  
56.   // Push the whole group back to Undo stack
57.   SetLength(UndoStack, Length(UndoStack) + 1);
58.   UndoStack[High(UndoStack)] := LastActions;
59.  
60.   // Reapply all actions
61.   for i := 0 to High(LastActions) do
62.   begin
63.     Act := LastActions[i];
64.     Form1.WorksheetGrid.Cells[Act.Col, Act.Row] := Act.NewValue;
65.   end;
66.  
67.   // Update edit box to show the new value of the last edited cell
68.   if Length(LastActions) > 0 then
69.   begin
70.     Act := LastActions[High(LastActions)];
71.   end;
72. end;
73.  
74. procedure TForm1.WorksheetGridEditingDone(Sender: TObject);
75. var
76.   Action_: TCellEdit_;
77.   CurrentValue: variant;
78. begin
79.   CurrentValue := WorksheetGrid.Cells[WorksheetGrid.Col, WorksheetGrid.Row];
80.   edit1.Text := vartostr(OldCellValue);
81.   // Only record if value actually changed
82.   if vartostr(CurrentValue) <> vartostr(OldCellValue) then
83.   begin
84.     Action_.Row := WorksheetGrid.Row;
85.     Action_.Col := WorksheetGrid.Col;
86.     Action_.OldValue := OldCellValue;
87.     Action_.NewValue := CurrentValue;
88.  
89.     // Add a new group containing this single edit
90.     SetLength(UndoStack, Length(UndoStack) + 1);
91.     SetLength(UndoStack[High(UndoStack)], 1);
92.     UndoStack[High(UndoStack)][0] := Action_;
93.  
94.     // Clear redo stack when new edit is made (standard undo/redo behavior)
95.     SetLength(RedoStack, 0);
96.  
97.     //ShowMessage('add data');
98.   end;
99. end;
100.  
101. procedure TForm1.WorksheetGridSelectCell(Sender: TObject; aCol, aRow: integer;
102.   var CanSelect: boolean);
103. begin
104.   OldCellValue := WorksheetGrid.Cells[aCol, aRow];
105.  
106. end;
107.  
108.  
109.  

i hope this one usable for others, cheers!

Thank you