[SOLVED] Update ListView

[Pe3s]

Hello, I have written code that updates existing ListView entries. I wonder if I wrote it correctly, can I improve the code?

Code: Pascal  [Select][+][-]

1. procedure TForm1.BitBtn2Click(Sender: TObject);
2. var
3.   ListItem: TListItem;
4. begin
5. ListView1.Items.Delete(ListView1.Selected.Index);
6. ListItem := ListView1.Items.Add;
7.  ListItem.Caption := Edit1.Text;
8.  ListItem.SubItems.Add(Edit2.Text);
9.  ListItem.SubItems.Add(Edit3.Text);
10.  ListItem.SubItems.Add(Edit4.Text);
11.  SaveData;              
12.  

[korba812]

You can just update the selected item:

Code: Pascal  [Select][+][-]

1. procedure TForm1.BitBtn2Click(Sender: TObject);
2. begin
3.   if ListView1.Selected <> nil then
4.     with ListView1.Selected do
5.     begin
6.       Caption := Edit1.Text;
7.       SubItems[0] := Edit2.Text;
8.       SubItems[1] := Edit3.Text;
9.       SubItems[2] := Edit4.Text;
10.     end;
11. end;

[dseligo]

One more thing.
Korba812 included it in his code, but he didn't mention it: you have to check if there is something selected or you'll get 'access violation':

Code: Pascal  [Select][+][-]

1. if ListView1.Selected <> nil then

[dseligo]

You can just update the selected item:

You should also protect subitems unless you always have 3 subitems:

Code: Pascal  [Select][+][-]

1. procedure TForm1.BitBtn2Click(Sender: TObject);
2. begin
3.   if ListView1.Selected <> nil then
4.     If ListView1.Selected.SubItems.Count < 3 then begin
5.       ShowMessage('Less then 3 subitems.');
6.       Exit;
7.     end;
8.     with ListView1.Selected do
9.     begin
10.       Caption := Edit1.Text;
11.       SubItems[0] := Edit2.Text;
12.       SubItems[1] := Edit3.Text;
13.       SubItems[2] := Edit4.Text;
14.     end;
15. end;

[ASerge]

Why not use local variables? Safe and fast.

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var
3.   Selected: TListItem;
4.   SubItems: TStrings;
5. begin
6.   Selected := ListView1.Selected;
7.   if Selected = nil then
8.     Exit;
9.   Selected.Caption := Edit1.Text;
10.   SubItems := Selected.SubItems;
11.   SubItems.Clear;
12.   SubItems.Append(Edit2.Text);
13.   SubItems.Append(Edit3.Text);
14.   SubItems.Append(Edit4.Text);
15. end;

[Pe3s]

Thank you