private void Form1_Load(object sender, EventArgs e)
        {
            fpSpread1.Sheets[0].Cells[0, 0].Value = 3;
            fpSpread1.Sheets[0].Cells[1, 0].Value = 2;
            fpSpread1.Sheets[0].Cells[1, 1].Value = 10;
            fpSpread1.Sheets[0].Cells[0, 2].Value = 1;            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //Error and No Error CF
            FarPoint.Win.Spread.ErrorConditionalFormattingRule error = new FarPoint.Win.Spread.ErrorConditionalFormattingRule(true);                       
            error.IsError = true;
            error.BackColor = Color.Yellow;
            fpSpread1.ActiveSheet.SetConditionalFormatting(1, 1, error);
        }

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        FpSpread1.Sheets(0).Cells(0, 0).Value = 3
        FpSpread1.Sheets(0).Cells(1, 0).Value = 2
        FpSpread1.Sheets(0).Cells(1, 1).Value = 10
        FpSpread1.Sheets(0).Cells(0, 2).Value = 1
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Error and No Error CF
        Dim error1 As New FarPoint.Win.Spread.ErrorConditionalFormattingRule(True)
        error1.IsError = True
        error1.BackColor = Color.Yellow
        FpSpread1.ActiveSheet.SetConditionalFormatting(1, 1, error1)
    End Sub