check if an item has been selected in ListBox

Question

I want to check if an item has been selected in ListBox when user click on label if i execute like that i got this error `list index out of bounds` ``` procedure TfrMain.Label15Click(Sender: TObject); var saveDialog : TSaveDialog; FileContents: TStringStream; saveLine,Selected : String; begin saveDialog := TSaveDialog.Create(self); saveDialog.Title := 'Save your text or word file'; saveDialog.InitialDir := GetCurrentDir; saveDialog.Filter := 'text file|*.txt'; saveDialog.DefaultExt := 'txt'; saveDialog.FilterIndex := 1; Selected := ListBox1.Items.Strings[ListBox1.ItemIndex]; if Selected <> '' then begin if saveDialog.Execute then begin FileContents := TStringStream.Create('', TEncoding.UTF8); FileContents.LoadFromFile(ListBox1.Items.Strings[ListBox1.ItemIndex]); FileContents.SaveToFile(saveDialog.Filename); ShowMessage('File : '+saveDialog.FileName) end else ShowMessage('Save file was not succesful'); saveDialog.Free; end; end; ```

Accepted Answer

This code

```
if Selected then
```

will not compile because `Selected` is a string. I guess you were experimenting just before posting this.

All the same you error messages and the question title suggests that `ListBox1.ItemIndex` is equal to -1. Hence the list index out of bounds error.

You need to add a check that `ListBox1.ItemIndex` is not -1 before reading from the list box. `ItemIndex=-1` is the way you detect that no item is selected. Your code should therefore look like this:

```
.....
saveDialog.DefaultExt := 'txt';  
saveDialog.FilterIndex := 1; 
if ListBox1.ItemIndex <> -1 then
begin
.....
```

check if an item has been selected in ListBox

Solution

Problem