TStringGrid的Rows索引值 和 Cells的 索引值， Row的赋值

  Caption := sgShopList.Rows[sgShopList.RowCount +].CommaText;

Caption := sgShopList.Rows[sgShopList.RowCount -1000].CommaText;

Rows[]的索引值，可以超过 RowCount，但是不能 小于0

Cells[]的索性值，读取时可以任意，包括-1 或者10000，不会报错。

  with TStringGrid.Create(Self )do
  try
    Parent := Self;
    ShowMessage( Cells[-, ] );
  finally
    free
  end;

function TStringGrid.GetCells(ACol, ARow: Integer): string;
var
  ssl: TStringSparseList;
begin
  ssl := TStringSparseList(TSparseList(FData)[ARow]);
  if ssl = nil then Result := '' else Result := ssl[ACol];
end;

写入时，不能是 -1，但可以是 100000等

  with TStringGrid.Create(Self )do
  try
    Parent := Self;
     Cells[, ] := '';
     ShowMessage( Cells[, ] );
  finally
    free
  end;

function TSparseList.Get(Index: Integer): Pointer;
begin
if Index <  then TList.Error(SListIndexError, Index);
Result := FList[Index]
end;

    property Row: Longint read FCurrent.Y write SetRow;

procedure TCustomGrid.SetRow(Value: Longint);
begin
  if Row <> Value then FocusCell(Col, Value, True);
end;

procedure TCustomGrid.FocusCell(ACol, ARow: Longint; MoveAnchor: Boolean);
begin
MoveCurrent(ACol, ARow, MoveAnchor, True);
UpdateEdit;
Click;
end;

procedure TCustomGrid.MoveCurrent(ACol, ARow: Longint; MoveAnchor,
  Show: Boolean);
var
  OldSel: TGridRect;
  OldCurrent: TGridCoord;
begin
  if (ACol < ) or (ARow < ) or (ACol >= ColCount) or (ARow >= RowCount) then
    InvalidOp(SIndexOutOfRange);
  if SelectCell(ACol, ARow) then
  begin
    OldSel := Selection;
    OldCurrent := FCurrent;
    FCurrent.X := ACol;
    FCurrent.Y := ARow;
    if not (goAlwaysShowEditor in Options) then HideEditor;
    if MoveAnchor or not (goRangeSelect in Options) then
    begin
      FAnchor := FCurrent;
      if goRowSelect in Options then FAnchor.X := ColCount - ;
    end;
    if goRowSelect in Options then FCurrent.X := FixedCols;
    if Show then ClampInView(FCurrent);
    SelectionMoved(OldSel);
    with OldCurrent do InvalidateCell(X, Y);
    with FCurrent do InvalidateCell(ACol, ARow);
  end;
end;