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TMemo - How to add lines of text without scrolling

Posted on 2004-09-06
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Last Modified: 2008-03-17
Using a TMemo component, and the .Lines.Add method to add text to the component, how do I keep the TMemo from scrolling downward as I add new text to the component?  In other words, if I use .Lines.Add 1000 times, the top line of the TMemo will be out of sight, and the last line will be visible in the TMemo.  I would prefer if the TMemo would cease scrolling while new lines are added.  Yes, I know how to rescroll the viewport/scrollbar back to the top, but this causes a flicker, and I'd much prefer to keep the TMemo frozen until all the new text has been added to it.

How can I perform this?

Thanks.
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Question by:Monroe406
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3 Comments
 
LVL 4

Expert Comment

by:Evarest
ID: 11991275
Maybe best to add these lines to a TStringList first and then copy its contents to your memo. This will be _a lot_ faster and you won't have any flickering to worry about...

procedure Add1000Lines;
var
 Q: integer;
 List: TStringList;
begin
 List :=TStringList.Create;
 for Q :=0 to 999 do
  begin
   List.Add(inttostr(Q));
  end;
 Memo1.Lines.AddStrings(List);
 List.Clear;
 List.Free;
end;

Of course, you'll need to alter this code to suite your needs...

Kind regards,
Evarest
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LVL 4

Accepted Solution

by:
Evarest earned 50 total points
ID: 11991285
BTW, you can "freeze" the memo by calling BeginUpdate and EndUpdate:

procedure Add1000Lines;
var
 Q: integer;
begin
 Memo1.Lines.BeginUpdate;
 try
  for Q :=0 to 999 do
   begin
    Memo1.Lines.Add(inttostr(Q));
   end;
 finally
  Memo1.Lines.EndUpdate;
 end;
end;

Evarest

0
 

Author Comment

by:Monroe406
ID: 11991329
The BeginUpdate / EndUpdate methods are all I really need.  Adding these 2 lines before and after my .Lines.Add will meet my needs.  Thanks.
0

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