[SOLVED] Undo/redo in TSTringGrid with TStream

[carlangas]

I am sure this must be obvious, but I couldn't manage to find out an easy way to implement undo/redo in a StringGrid using TStream, which I see in this forum as a convenient solution.

This is what I do:

Code: Pascal  [Select][+][-]

1. var
2.  Copia: TMemoryStream;
3.  
4. ...
5.  
6. Copia:=TMemoryStream.Create;
7.  
8. ...
9.  
10.  
11. LaTabla.SaveToStream(Copia);
12.  
13. ...
14.  
15. LaTabla.LoadFromStream(Copia);
16.  
17.  

When loading from the stream, I get an

Code: Pascal  [Select][+][-]

1. In 'stream:' (line 1 pos 1): Root element is missing.

error.

What I want to do is to back up the content of the grid and be able to restore it.

What is the mistake I make?

[bobby100]

Dunno if SaveOptions are affecting the SaveToStream, but this looks like SaveOptions problem.

[jamie]

Did you reset the Position back to 0 before trying to reload it?

[carlangas]

Exactly. It was that. I did not manage to find a usage example for doing so.

It was just a matter of doing

Code: Pascal  [Select][+][-]

1. Copia.Position:=0;

before loading it back.

So, for anyone having the same issue and not finding the needed doc, this is how I end up doing it:

Code: Pascal  [Select][+][-]

1. var
2.  Copia: TMemoryStream;
3.  
4. ...
5.  
6. Copia:=TMemoryStream.Create;
7.  
8. ...
9.  
10.  
11. LaTabla.SaveToStream(Copia);
12.  
13. ...
14.  
15. Copia.Position:=0;
16. LaTabla.LoadFromStream(Copia);
17.  

Thanks, Jamie.