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Report From: Delphi-BCB/VCL/Standard Controls/TMemo    [ Add a report in this area ]  
Report #:  89722   Status: Closed
TMemoStrings.Insert() fails to insert blank strings at times.
Project:  Delphi Build #:  6, 2010, XE
Version:    15.0 Submitted By:   Remy Lebeau (TeamB)
Report Type:  Basic functionality failure Date Reported:  11/16/2010 7:09:09 PM
Severity:    Infrequently encountered problem Last Updated: 3/20/2012 2:24:39 AM
Platform:    All platforms Internal Tracking #:   281239
Resolution: Fixed (Resolution Comments) Resolved in Build: :
Duplicate of:  None
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Description
When using TMemo.Lines.Add() to insert blank strings, sometimes they are
ignored.

This has been reproduced in XE Update 1, D2010 Update 4/5, and even in
BCB 6 Update 4!
Steps to Reproduce:
Place a TMemo on a TForm and leave it empty.  Name it 'Memo1'.

Add a TButton to the same form.  Name it 'Button1'.

Add the following OnClick event handler to Button1:

procedure TForm1.Button1Click(Sender: TObject);
begin
  Memo1.Lines.Add('2nd line');
  Memo1.Lines.Add('');
  Memo1.Lines.Add('4th line');
  Memo1.Lines.Add('');
  Memo1.Lines.Add('6th line');
end;

Start the program and enter *one* line of text into the memo, e.g. '1st line', *without* hitting return. Your cursor should thus still be somewhere in line 1 of the memo.

Click Button1

You'll find that the memo now holds these contents:

1st line (or whatever text you entered)
2nd line
4th line

6th line

As you can see, the first blank line added during runtime is omitted.
Workarounds
Added by Sysop
<<<<<<<<<
Please see Patch in [Attachments].
>>>>>>>>>
Attachment
MemoLinesError.zip
Comments

Tomohiro Takahashi at 11/17/2010 12:01:25 AM -
Please try #13 instead of '' as below.
----
  Memo1.Lines.Add('2nd line');
  Memo1.Lines.Add(#13);
  Memo1.Lines.Add('4th line');
  Memo1.Lines.Add(#13);
  Memo1.Lines.Add('6th line');
----

Remy Lebeau (TeamB) at 11/18/2010 6:21:42 PM -
That does work, but it is a workaround, not a fix.  Mark Edington came up with a patch that does fix the error.  I have attached it.

Dick Boogaers at 11/19/2010 3:29:52 AM -
Why don't you write down the patch in plain English.
Then everyone with any version of StdCtrls could have a look if it can be improved.

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