Lazarus

Programming => LCL => Topic started by: madref on March 24, 2019, 11:21:32 pm

Title: [SOLVED] TMemo & Line Index
Post by: madref on March 24, 2019, 11:21:32 pm

I am doing a search in a Tmemo with the following code

Code: Pascal  [Select][+][-]

1. function TForm_Test.FindInMemo(AMemo: TMemo; AString: String; StartPos: Integer): Integer;
2. begin
3.   Result := PosEx(AString, AMemo.Text, StartPos);
4.   if Result > 0 then begin
5.     AMemo.SelStart := UTF8Length(PChar(AMemo.Text), Result - 1);
6.     AMemo.SelLength := Length(AString);
7.     AMemo.SetFocus;
8.   end;  // if
9. end;     // FindInMemo

This gives me a number which is from the start of the Tmemo.


But how can I determine the linenumber from this?
I found this but this is for Delphi and not Lazarus.

Code: Pascal  [Select][+][-]

1. mi := Memo_Test.Perform(EM_LINEFROMCHAR, i, 0);

Title: Re: TMemo & Line Index
Post by: lucamar on March 25, 2019, 12:27:37 am

Only way I know of is to read CaretPos after you set SelStart but before setting SelLength.

It may or may not work for all platforms: In GTK, for example, setting selections sometimes works ... "funny". :)

Title: Re: TMemo & Line Index
Post by: engkin on March 25, 2019, 01:14:03 am

Quote from: madref on March 24, 2019, 11:21:32 pm

I am doing a search in a Tmemo with the following code

Code: Pascal  [Select][+][-]

1. function TForm_Test.FindInMemo(AMemo: TMemo; AString: String; StartPos: Integer): Integer;
2. begin
3.   Result := PosEx(AString, AMemo.Text, StartPos);
4.   if Result > 0 then begin
5.     AMemo.SelStart := UTF8Length(PChar(AMemo.Text), Result - 1);
6.     AMemo.SelLength := Length(AString);
7.     AMemo.SetFocus;
8.   end;  // if
9. end;     // FindInMemo

This gives me a number which is from the start of the Tmemo.

FindInMemo has a little bug:

Code: Pascal  [Select][+][-]

1.     AMemo.SelLength := UTF8Length(AString);

Quote from: madref on March 24, 2019, 11:21:32 pm

But how can I determine the linenumber from this?
I found this but this is for Delphi and not Lazarus.

Code: Pascal  [Select][+][-]

1. mi := Memo_Test.Perform(EM_LINEFROMCHAR, i, 0);

For Windows, use SendMessage:

Code: Pascal  [Select][+][-]

1.   mi := SendMessage(Memo_Test.Handle, EM_LINEFROMCHAR, i, 0);

i has to be for UTF16, but if you pass -1 instead of i, you get the line that has the caret/selection, without caring about UTF16.

Title: Re: TMemo & Line Index
Post by: madref on March 25, 2019, 05:21:42 am

But unfortunately I don't have a windows version.
I am using a Mac on OSx Mojave


Therefor EM_LINEFROMCHAR is not defined anywhere

Title: Re: TMemo & Line Index
Post by: sstvmaster on March 25, 2019, 10:15:30 am

Something like that?

Code: Pascal  [Select][+][-]

1. function TForm_Test.FindInMemo(AMemo: TMemo; AString: String; StartPos: Integer): Integer;
2. var
3.   vPos: integer;
4. begin
5.   AMemo.HideSelection := false; // no focus needed to show selected
6.   vPos := PosEx(AString, AMemo.Text, StartPos);
7.   if vPos > 0 then begin
8.     AMemo.SelStart := UTF8Length(PChar(AMemo.Text), vPos - 1);
9.     AMemo.SelLength := UTF8Length(AString);
10.     Result := AMemo.CaretPos.Y; // !!! It starts from 0 (zero) !!!
11.   end;
12. end;

Greetings Maik

Title: Re: TMemo & Line Index
Post by: howardpc on March 25, 2019, 10:59:05 am

I think better would be

Code: Pascal  [Select][+][-]

1. function FindMemoLineNumber(AMemo: TMemo; const AString: String; StartPos: Integer): Integer;
2. begin
3.   AMemo.HideSelection := False;
4.   Result := PosEx(AString, AMemo.Text, StartPos);
5.   case Result of
6.     0: Exit(-1);
7.     else
8.       begin
9.         AMemo.SelStart := UTF8Length(PChar(AMemo.Text), Pred(Result));
10.         AMemo.SelLength := UTF8Length(AString);
11.         Result := Succ(AMemo.CaretPos.Y); // indexed from 1
12.       end;
13.     end;
14. end;

Note that this is dependent on the setting of AMemo.WordWrap. WordWrap should be False for reliable results.

Title: Re: TMemo & Line Index
Post by: madref on March 25, 2019, 10:45:50 pm

Thanks everyone.... it works