Public Enum UnderlineFontStyle 
   Inherits System.Enum

Dim instance As UnderlineFontStyle

public enum UnderlineFontStyle : System.Enum 

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;      

        FarPoint.Win.Spread.UnaryComparisonConditionalFormattingRule unary = new FarPoint.Win.Spread.UnaryComparisonConditionalFormattingRule(FarPoint.Win.Spread.UnaryComparisonOperator.EqualTo, 10, false);
        unary.Operator = FarPoint.Win.Spread.UnaryComparisonOperator.EqualTo;
        unary.Value = 10;
        unary.BackColor = System.Drawing.Color.Red;
        unary.FontStyle = new FarPoint.Win.Spread.SpreadFontStyle(FarPoint.Win.Spread.RegularBoldItalicFontStyle.Bold, FarPoint.Win.Spread.StrikeoutFontStyle.Strikeout, FarPoint.Win.Spread.UnderlineFontStyle.Underline);

        FarPoint.Win.Spread.BetweenValuesConditionalFormattingRule between = new FarPoint.Win.Spread.BetweenValuesConditionalFormattingRule(false, 1, false, 20, false);
        between.FirstValue = 1;
        between.SecondValue = 20;
        between.IsNotBetween = true;
        between.BackColor = System.Drawing.Color.Bisque;

        //SetConditionalFormatting Overload
        fpSpread1.ActiveSheet.SetConditionalFormatting(0, 0, 3, 3, false, unary, between);
        }

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

        Dim unary As New FarPoint.Win.Spread.UnaryComparisonConditionalFormattingRule(FarPoint.Win.Spread.UnaryComparisonOperator.EqualTo, 10, False)
        unary.Operator = FarPoint.Win.Spread.UnaryComparisonOperator.EqualTo
        unary.Value = 10
        unary.BackColor = Drawing.Color.Red
        unary.FontStyle = New FarPoint.Win.Spread.SpreadFontStyle(FarPoint.Win.Spread.RegularBoldItalicFontStyle.Bold, FarPoint.Win.Spread.StrikeoutFontStyle.Strikeout, FarPoint.Win.Spread.UnderlineFontStyle.Underline)

        Dim between As New FarPoint.Win.Spread.BetweenValuesConditionalFormattingRule(False, 1, False, 20, False)
        between.FirstValue = 1
        between.SecondValue = 20
        between.IsNotBetween = True
        between.BackColor = Drawing.Color.Bisque

        'SetConditionalFormatting Overload
        FpSpread1.ActiveSheet.SetConditionalFormatting(0, 0, 3, 3, False, unary, between)
    End Sub