Сортировка ListView

Code:

{

This example shows how to use the TListView's CustomSort method to

sort the items in the list using a ordering function.

This allows you to sort custom data in the correct order you want.

When the user clicks on a column header, the ListView will be sorted

by that column.

If the user clicks on the same column again, the sort order will be toggled.

}

{ custom sort styles }

type

  TCustomSortStyle = (cssAlphaNum, cssNumeric, cssDateTime);

var

  { variable to hold the sort style }

  LvSortStyle: TCustomSortStyle;

  { array to hold the sort order }

  LvSortOrder: array[0..4] of Boolean; // High[LvSortOrder] = Number of Lv Columns

implementation

{$R *.DFM}

function CustomSortProc(Item1, Item2: TListItem; SortColumn: Integer): Integer; stdcall;

var

  s1, s2: string;

  i1, i2: Integer;

  r1, r2: Boolean;

  d1, d2: TDateTime;

  { Helper functions }

  function IsValidNumber(AString : string; var AInteger : Integer): Boolean;

  var

    Code: Integer;

  begin

    Val(AString, AInteger, Code);

    Result := (Code = 0);

  end;

  function IsValidDate(AString : string; var ADateTime : TDateTime): Boolean;

  begin

    Result := True;

    try

      ADateTime := StrToDateTime(AString);

    except

      ADateTime := 0;

      Result := False;

    end;

  end;

  function CompareDates(dt1, dt2: TDateTime): Integer;

  begin

    if (dt1 > dt2) then Result := 1

    else

      if (dt1 = dt2) then Result := 0

    else

      Result := -1;

  end;

  function CompareNumeric(AInt1, AInt2: Integer): Integer;

  begin

    if AInt1 > AInt2 then Result := 1

    else

      if AInt1 = AInt2 then Result := 0

    else

      Result := -1;

  end;

begin

  Result := 0;

  if (Item1 = nil) or (Item2 = nil) then Exit;

  case SortColumn of

    -1 :

    { Compare Captions }

    begin

      s1 := Item1.Caption;

      s2 := Item2.Caption;

    end;

    else

    { Compare Subitems }

    begin

      s1 := '';

      s2 := '';

      { Check Range }

      if (SortColumn < Item1.SubItems.Count) then

        s1 := Item1.SubItems[SortColumn];

      if (SortColumn < Item2.SubItems.Count) then

        s2 := Item2.SubItems[SortColumn]

    end;

  end;

  { Sort styles }

  case LvSortStyle of

    cssAlphaNum : Result := lstrcmp(PChar(s1), PChar(s2));

    cssNumeric  : begin

                    r1 := IsValidNumber(s1, i1);

                    r2 := IsValidNumber(s2, i2);

                    Result := ord(r1 or r2);

                    if Result <> 0 then

                      Result := CompareNumeric(i2, i1);

                  end;

    cssDateTime : begin

                    r1 := IsValidDate(s1, d1);

                    r2 := IsValidDate(s2, d2);

                    Result := ord(r1 or r2);

                    if Result <> 0 then

                      Result := CompareDates(d1, d2);

                  end;

  end;

  { Sort direction }

  if LvSortOrder[SortColumn + 1] then

    Result := - Result;

end;

{ The ListView's OnColumnClick event }

procedure TForm1.ListView1ColumnClick(Sender: TObject; Column: TListColumn);

begin

  { determine the sort style }

  if Column.Index = 0 then

    LvSortStyle := cssAlphaNum

  else

    LvSortStyle := cssNumeric;

  { Call the CustomSort method }

  ListView1.CustomSort(@CustomSortProc, Column.Index -1);

  { Set the sort order for the column}

  LvSortOrder[Column.Index] := not LvSortOrder[Column.Index];

end;