[SOLVED] ListView + Drag and Drop

[Vingadero]

Hello,

I'm trying to do this code in this article: http://delphi.about.com/od/vclusing/a/arrangelistview.htm

Code: [Select]

//ListView OnDragDrop
procedure TListViewForm.ListView1DragDrop(Sender, Source: TObject; X, Y: Integer) ;
var
   currentItem, nextItem, dragItem, dropItem : TListItem;
begin
   if Sender = Source then
   begin
     with TListView(Sender) do
     begin
       dropItem := GetItemAt(X, Y) ;
       currentItem := Selected;
       while currentItem <> nil do
       begin
         nextItem := GetNextItem(currentItem, SdAll, [IsSelected]) ;
         if Assigned(dropItem) then
           dragItem := Items.Insert(dropItem.Index)
         else
           dragItem := Items.Add;
         dragItem.Assign(currentItem) ;
         currentItem.Free;
         currentItem := nextItem;
       end;
     end;
   end;
end;
IsSelected I have change to lisSelected.

But when I drag it, the program enter in a infinite loop on while currentItem <> nil do...

How can I adapt this code to lazarus?

thx in advance

[vcunha]

Hello Vingadero

I do not know a method to find the next item in a TListView in Lazarus, but the code below can help you.

Code: [Select]

procedure TListViewForm.ListView1DragDrop(Sender, Source: TObject; X, Y: Integer
  );
var
  currentItem, nextItem, dragItem, dropItem : TListItem;
  i: integer;
begin
  if Sender = Source then
  begin
    with TListView(Sender) do
    begin
      dropItem := GetItemAt(X, Y) ;
      currentItem := Selected;
      while currentItem <> nil do
      begin
        nextItem := nil;
        for i := 0 to Items.Count - 1 do begin
         if (Items[i].Selected) and (currentItem.Index <> i) then begin
           nextItem := Items[i];
           break;
         end;
        end;
        if Assigned(dropItem) then
          dragItem := Items.Insert(dropItem.Index)
        else
          dragItem := Items.Add;
        dragItem.Assign(currentItem) ;
        currentItem.Free;
        currentItem := nextItem;
      end;
    end;
  end;
end;

If you find a better way, please share with us. I'm always learning more.

Greetings.

VCunha.

[Vingadero]

Sweet, works like a charm

Ty

[kandukeswara]

Thanks guys, this topic is help me 
And.. you can add this code, so user can see which record has been moved :

Code: Pascal  [Select][+][-]

1. dragItem.Selected:=True;

This is the complete code :

Code: Pascal  [Select][+][-]

1. //ListView OnDragDrop
2. procedure TListViewForm.ListView1DragDrop(Sender, Source: TObject; X, Y: Integer) ;
3. var
4.   currentItem, nextItem, dragItem, dropItem : TListItem;
5.   i: integer;
6. begin
7.   if Sender = Source then
8.   begin
9.     with TListView(Sender) do
10.     begin
11.       dropItem := GetItemAt(X, Y) ;
12.       currentItem := Selected;
13.       while currentItem <> nil do
14.       begin
15.         nextItem := nil;
16.         for i := 0 to Items.Count - 1 do begin
17.          if (Items[i].Selected) and (currentItem.Index <> i) then begin
18.            nextItem := Items[i];
19.            break;
20.          end;
21.         end;
22.         if Assigned(dropItem) then
23.           dragItem := Items.Insert(dropItem.Index)
24.         else
25.           dragItem := Items.Add;
26.         dragItem.Assign(currentItem) ;
27.  
28.         dragItem.Selected:=True;
29.  
30.         currentItem.Free;
31.         currentItem := nextItem;
32.       end;
33.     end;
34.   end;
35. end;
36.  
37. procedure TListViewForm.ListView1DragOver(Sender, Source: TObject; X,
38.   Y: Integer; State: TDragState; var Accept: Boolean);
39. begin
40.   Accept := Sender = TListView(Sender);
41. end;

Greetings
Bayu K