TdxListViewCompareEvent Type

The item comparison procedural type.

Declaration

TdxListViewCompareEvent = procedure(Sender: TdxCustomListView; AItem1: TdxListItem; AItem2: TdxListItem; AData: TdxNativeInt; var ACompare: Integer) of object;

Parameters

Name	Type	Description
Sender	TdxCustomListView	The List View control that raised an item comparison event.
AItem1	TdxListItem	The first target list item.
AItem2	TdxListItem	The second target list item.
AData	TdxNativeInt	Specifies a pointer to additional data for the custom comparison routine.
ACompare	Integer	A result of the comparison.

Remarks

The following table explains which ACompare parameter values correspond to specific comparison results:

Value	Description
A negative integer value	AItem1 is positioned before AItem2.
0	AItem1 is positioned before AItem2.
A positive integer value	AItem is positioned after AItem2.

The following OnCompare event handler sorts items by captions in the specified sort order if the control displays columns:

Delphi

procedure TForm1.dxListViewControl1Compare(Sender: TdxCustomListView; AItem1,
  AItem2: TdxListItem; AData: Integer; var ACompare: Integer);
begin
  ACompare := CompareStr(AItem1.Caption, AItem2.Caption);
  if (Sender.ViewStyle = TdxListViewStyle.Report) and (Sender.Columns.Count <> 0) then
    if Sender.Columns[0].SortOrder = soDescending then
      ACompare := ACompare * -1;
end;

C++

void __fastcall TForm1::dxListViewControl1Compare(TdxCustomListView *Sender, TdxListItem *AItem1, 
  TdxListItem *AItem2, NativeInt AData, int &ACompare);
{
  ACompare = AItem1->Caption > AItem2->Caption;
  if (Sender->ViewStyle == TdxListViewStyle::Report && Sender->Columns->Count != 0)
    if (Sender->Columns->Items[0]->SortOrder == soDescending)
      ACompare = ACompare * -1;
}

The List View’s OnCompare event references the TdxListViewCompareEvent type.