Sub AddSelection( _
   ByVal row As Integer, _
   ByVal column As Integer, _
   ByVal rowCount As Integer, _
   ByVal columnCount As Integer _
) 

Dim instance As ISheetSelectionModel
Dim row As Integer
Dim column As Integer
Dim rowCount As Integer
Dim columnCount As Integer
 
instance.AddSelection(row, column, rowCount, columnCount)

void AddSelection( 
   int row,
   int column,
   int rowCount,
   int columnCount
)

FarPoint.Win.Spread.Model.ISheetSelectionModel sel;
DialogResult dlg;
sel = (FarPoint.Win.Spread.Model.ISheetSelectionModel)fpSpread1.ActiveSheet.Models.Selection;
sel.AddSelection(0, 0, 2, 2);
dlg = MessageBox.Show("Do you want to extend the selection?", "ExtendSelection", MessageBoxButtons.YesNo);
if (dlg == DialogResult.Yes)
{
sel.ExtendSelection(4, 4);
}

Dim sel As FarPoint.Win.Spread.Model.ISheetSelectionModel
Dim dlg As DialogResult
sel = FpSpread1.ActiveSheet.Models.Selection
sel.AddSelection(0, 0, 2, 2)
dlg = MessageBox.Show("Do you want to extend the selection?", "ExtendSelection", MessageBoxButtons.YesNo)
If dlg = DialogResult.Yes Then
sel.ExtendSelection(4, 4)
End If