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help! WriteLN  to write to a specific line in text file

Posted on 2003-11-23
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747 Views
Last Modified: 2010-04-03
hi

I am trying to write a program with a checkbox, so that when the checkbox is clicked the following is written to a text file

Dave speaks good english true;

if the checkbox is unclicked

Dave speaks good english false;

When using WriteLn it writes to the first line of the text file i have specified, but i want to write to another line, for example, line 10. I have the following code which i couldnt get to work.


procedure Tform1.CheckBox1Click(Sender: TObject);

var
txt:textfile;
line:string;

begin
assignfile(txt, '/home/user/test.txt');
rewrite(txt);

if checkbox1.checked then

line:='dave speaks good english true;';
Writeln(txt, line)

end

else

line :='dave speaks good english false;';
Writeln(txt,line);
end

closefile(txt);
end;
end.

My first problem is that i cant seem to use the if else statement to write a line to a text file if the checkbox is clicked if not clicked write a different line to a text file, and the second problem is that i dont know how i could change my code to write to another line of the text file rather then line 1, for example line 10.   Thanks in advance!!

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Question by:itektas
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4 Comments
 
LVL 8

Expert Comment

by:gmayo
ID: 9805874
You need begin...end blocks in your IF statement:

if checkbox1.checked then begin

line:='dave speaks good english true;';
Writeln(txt, line)

end

else begin

line :='dave speaks good english false;';
Writeln(txt,line);
end

Geoff M.
0
 

Author Comment

by:itektas
ID: 9805888
ok cool ill try that now, but what about if i want to enter the information in a certain line other then the first one, Writeln writes into the first line of the text file, how would i write to line 10 ? is that possible? thanks
0
 
LVL 8

Accepted Solution

by:
gmayo earned 30 total points
ID: 9806007
I think you can open the file in read/write mode, read 9 lines, and write the 10th. However, if the new line is shorter, I think you'll have part of the old line left over.

Perhaps a better option would be to use a TStringList.

var sl : TStringList;

sl := TStringList.Create;
sl.LoadFromFile('filename.txt');
sl[9] := 'whatever you want';
sl.SaveToFile('filename.txt');
sl.Free;

Geoff M.
0
 

Author Comment

by:itektas
ID: 9806179
perfect. thanks a lot :)
0

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