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.ThreeColorScaleConditionalFormattingRule three = new FarPoint.Win.Spread.ThreeColorScaleConditionalFormattingRule();
three.MidValue = new FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.Aqua, 5, FarPoint.Win.Spread.ConditionalFormattingValueType.Number);
three.MinValue = new FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.BlueViolet, 1, FarPoint.Win.Spread.ConditionalFormattingValueType.Number);
three.MaxValue = new FarPoint.Win.Spread.ConditionalFormattingColorValue(Color.Purple, 10, FarPoint.Win.Spread.ConditionalFormattingValueType.Number);
fpSpread1.Sheets[0].SetConditionalFormatting(0, 0, 3, 3,three);