TdxListViewCompareEvent Type

The item comparison procedural type.

Declaration

delphi

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
C++

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;

cpp

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.