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)
    {
        FarPoint.Win.Spread.Model.CellRange celRange1 = new FarPoint.Win.Spread.Model.CellRange(0, 0, 3, 3);
        FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule rule = new FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule(Color.Aqua, Color.Bisque, Color.BlueViolet);
        fpSpread1.Sheets[0].SetConditionalFormatting(new FarPoint.Win.Spread.Model.CellRange[] { celRange1 }, rule);
        //or
        //FarPoint.Win.Spread.Model.CellRange celRange1 = new FarPoint.Win.Spread.Model.CellRange(0, 0, 3, 3);
        //FarPoint.Win.Spread.Model.CellRange celRange2 = new FarPoint.Win.Spread.Model.CellRange(0, 4, 2, 2);            
        //FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule rule = new FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule(Color.Aqua, Color.Bisque, Color.BlueViolet);
        //fpSpread1.Sheets[0].SetConditionalFormatting(new FarPoint.Win.Spread.Model.CellRange[] { celRange1, celRange2 }, rule);
        //or
        //FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule three = new FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule();
        //three.MidValue = new FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.Aqua, 10, FarPoint.Win.Spread.ConditionalFormattingValueType.Number);
        //three.MinValue = new FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.BlueViolet, 10, FarPoint.Win.Spread.ConditionalFormattingValueType.Number);
        //fpSpread1.Sheets[0].SetConditionalFormatting(1, 1, three);
    }

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
        Dim celRange1 As New FarPoint.Win.Spread.Model.CellRange(0, 0, 3, 3)
        Dim rule As New FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule(Color.Aqua, Color.Bisque, Color.BlueViolet)
        FpSpread1.Sheets(0).SetConditionalFormatting(New FarPoint.Win.Spread.Model.CellRange() {celRange1}, rule)
        'or
        'Dim celRange1 As New FarPoint.Win.Spread.Model.CellRange(0, 0, 3, 3)
        'Dim celRange2 As New FarPoint.Win.Spread.Model.CellRange(0, 4, 2, 2)
        'Dim rule As New FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule(Color.Aqua, Color.Bisque, Color.BlueViolet)
        'FpSpread1.Sheets(0).SetConditionalFormatting(New FarPoint.Win.Spread.Model.CellRange() {celRange1, celRange2}, rule)
        'or
        'Dim three As New FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule()
        'three.MidValue = New FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.Aqua, 10, FarPoint.Win.Spread.ConditionalFormattingValueType.Number)
        'three.MinValue = New FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.BlueViolet, 10, FarPoint.Win.Spread.ConditionalFormattingValueType.Number)
        'FpSpread1.Sheets(0).SetConditionalFormatting(1, 1, three)
    End Sub