Author: Tomas Rutkauskas

How to sort a TListView on a column header click

Answer:

In the object inspector, I have set the ListView's SortType = stText.

1   {Private Declarations}
2   SortColumn: Integer;
3   SortDescending: Boolean;
4   
5   procedure Sort(Column: Integer);
6   
7   procedure TfrmMain.ListViewColumnClick(Sender: TObject; Column: TListColumn);
8   begin
9     Sort(Column.Index);
10  end;
11  
12  procedure TfrmMain.Sort(Column: Integer);
13  begin
14    if SortColumn = Column then
15      SortDescending := not SortDescending
16    else
17    begin
18      SortDescending := False;
19      SortColumn := Column;
20    end;
21    lsvPlayerPages.AlphaSort;
22  end;
23  
24  procedure TfrmMain.ListViewCompare(Sender: TObject; Item1, Item2: TListItem;
25    Data: Integer; var Compare: Integer);
26  begin
27    if SortColumn = 0 then
28      Compare := CompareStr(Item1.Caption, Item2.Caption)
29    else
30      Compare := CompareStr(Item1.SubItems[Pred(SortColumn)],
31        Item2.SubItems[Pred(SortColumn)]);
32    if SortDescending then
33      Compare := -Compare;
34  end;


I have made a separate sort procedure to be able to sort from different commands (e.g. from a menu). The code also sorts descending if a column header is clicked a second time (as Windows Explorer does).