Public Sub SetFormula( _
   ByVal row As Integer, _
   ByVal column As Integer, _
   ByVal value As String _
) 

Dim instance As DefaultSheetDataModel
Dim row As Integer
Dim column As Integer
Dim value As String
 
instance.SetFormula(row, column, value)

public void SetFormula( 
   int row,
   int column,
   string value
)

Dim dataModel As New FarPoint.Win.Spread.Model.DefaultSheetDataModel(5, 5)
Dim o As Object
FpSpread1.ActiveSheet.Models.Data = dataModel
dataModel.SetValue(0, 0, 10)
dataModel.SetValue(1, 0, 20)
dataModel.SetFormula(0, 0, "3*SUM(A1, A2)")
o = dataModel.GetFormula(0, 0)
ListBox1.Items.Add(o.ToString())

FarPoint.Win.Spread.Model.DefaultSheetDataModel dataModel = new FarPoint.Win.Spread.Model.DefaultSheetDataModel(5, 5);
object o;
fpSpread1.ActiveSheet.Models.Data = dataModel;
dataModel.SetValue(0, 0, 10);
dataModel.SetValue(1, 0, 20);
dataModel.SetFormula(0, 0, "3*SUM(A1, A2)");
o = dataModel.GetFormula(0, 0);
listBox1.Items.Add(o.ToString());