List index (-1) out of bounds in ListBox

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Przemyslav:
Hello everybody. I have problem with my ListBox. I get error like this: "List index (-1) out of bounds", when I click on empty space in ListBox.

I have form like this:

https://i.postimg.cc/HW4H5HR3/Bez-tytu-u.png

My code:

--- Code: Pascal [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---unit Unit1;var Form1: TForm1; ulicekmp,ulicekmprecord : TStringList;

--- Code: Pascal [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---procedure TForm1.RadioGroup1Click(Sender: TObject);var i : integer;begin if (RadioGroup1.ItemIndex = 0) then begin if FileExists('dat\ulice0-9.dat') then begin ulicekmprecord:=TStringList.Create; ulicekmprecord.Delimiter:=';'; ulicekmprecord.StrictDelimiter:=true; ulicekmp:=TStringList.Create; ulicekmp.StrictDelimiter:=true;ulicekmp.LoadFromFile('dat\ulice0-9.dat'); ListBox1.Enabled := true; ListBox1.Clear; Memo1.Clear; for i:=0 to ulicekmp.Count-1 do begin ulicekmprecord.DelimitedText:=ulicekmp.Strings[i]; ListBox1.Items.Add(ulicekmprecord.Strings[0]); end; end else MessageDlg('Nie odnaleziono pliku: ' + ExtractFilePath(Application.ExeName) + 'dat\ulice0-9.dat' + '.' , mtError, [mbOk], 0 ); end;(...)

--- Code: Pascal [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---procedure TForm1.ListBox1Click(Sender: TObject);begin ulicekmprecord.DelimitedText:=ulicekmp.Strings[ListBox1.ItemIndex]; Memo1.Enabled := true; Memo1.Clear; Memo1.Append(ulicekmprecord.Strings[1]);end;
So I have file for example "ulice0-9.dat" where I have somethong like this:

--- Quote ---abcdefg;12345
hjhgjgfjf;767666
rrturturtitr;7767676
(...)
--- End quote ---

My file is opened in RadioGroup and imported to 2 stringlists ulicekmp,ulicekmprecord with delimited text (;). One part is imported to items of ListBox. When I click on non empty item in ListBox, my program display second part on Memo. I have error "List index (-1) out of bounds" when I click on empty space in ListBox after imported values:

https://i.postimg.cc/dDPTzFR5/Bez-tytu-u.png

How to remove this error?

Sorry for my English, thank you for your help :)

lucamar:
Try this:

--- Code: Pascal [+][-]window.onload = function(){var x1 = document.getElementById("main_content_section"); if (x1) { var x = document.getElementsByClassName("geshi");for (var i = 0; i < x.length; i++) { x[i].style.maxHeight='none'; x[i].style.height = Math.min(x[i].clientHeight+15,306)+'px'; x[i].style.resize = "vertical";}};} ---procedure TForm1.ListBox1Click(Sender: TObject);begin {Make sure there's an item selected before trying to use it} if ListBox1.ItemIndex >= 0 then begin ulicekmprecord.DelimitedText:=ulicekmp.Strings[ListBox1.ItemIndex]; Memo1.Enabled := true; Memo1.Clear; Memo1.Append(ulicekmprecord.Strings[1]); end;end;
Nota that this is just a minimal check! You should also check that ItemIndex is a valid index for ulicekmp.Strings, etc.

Przemyslav:
Thank you very much :) It's working in 2 cases - on item selected before and non selected. Thank you :)

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