This property is available at run time only.
fpSpread1.ActiveSheet.AddSelection(0, 0, 2, 2); fpSpread1.ActiveSheet.AddSelection(3, 0, 2, 2); listBox1.Items.Add(fpSpread1.ActiveSheet.SelectionCount.ToString());
FpSpread1.ActiveSheet.AddSelection(0, 0, 2, 2) FpSpread1.ActiveSheet.AddSelection(3, 0, 2, 2) ListBox1.Items.Add(FpSpread1.ActiveSheet.SelectionCount.ToString())