Question

I’m trying to round off the following values, but I don’t know what’s wrong.

NewValue -=(System.Math.Round(Global.WorkData.ValueOld - System.Math.Round (Global.WorkData.ValueOld * 20, 0) / 20, 2 ));

And this is what I did:

NewValue -=(System.Math.Round(Global.WorkData.ValueOld, 2, MidpointRounding.AwayFromZero - System.Math.Round(Global.WorkData.ValueOld * 20, 2,MidpointRounding.AwayFromZero) / 20, 2 ));

Could you please tell me what’s wrong in my code? why I can’t compile it?
Thanks

Answer 1

You’ve got at least one bracketing error, so it’s trying to subtract a decimal value from a MidpointRounding.

However, I still can’t work out what you’re really trying to do.

I strongly recommend that you split this statement up – split the calls to Round, and then one using the values. For example:

decimal oldValue = Global.WorkData.ValueOld; // For convenience
decimal roundTo2 = Math.Round(oldValue, 2, MidpointRounding.AwayFromZero);
decimal roundTo20 = Math.Round(oldValue * 20, 2, MidpointRounding.AwayFromZero);
newValue -= roundTo2 - (roundTo20/20);

I still can’t work out exactly what you want to do with the results – what’s the 2 at the end of the statement meant to be for? What is the first statement in your question meant to be? Maybe you want:

decimal oldValue = Global.WorkData.ValueOld; // For convenience
decimal roundedBy20ths = Math.Round(oldValue * 20, 2,
                                    MidpointRounding.AwayFromZero) / 20;
decimal remainder = Math.Round(oldValue - roundedBy20ths, 2,
                               MidpointRounding.AwayFromZero);
newValue -= remainder;

? That might be it, but I really don’t know…

Shorter statements make the code clearer and let you find this kind of error much more easily.