Question

I have a double and need to convert it to a decimal. If the value is too large/small the result should be decimal.MaxValue/decimal.MinValue. What is the best way to do this?

Answer 1

I assume you realize this is a lossy conversion, and should be avoided if possible? If you really need it:

private static readonly double MaxDecimalAsDouble = (double) decimal.MaxValue;
private static readonly double MinDecimalAsDouble = (double) decimal.MinValue;

...
public decimal ConvertWithCap(double input)
{
    return input >= MaxDecimalAsDouble ? decimal.MaxValue
         : input <= MinDecimalAsDouble ? decimal.MinValue
         : (decimal) input;
}

This way the cap is checked in terms of the double value, but then return the capped value hard-coded to be the decimal value. This avoids the problem where double can’t accurately represent the max/min values of decimal.

(Even at the largest scales of decimal, consecutive integers can be represented – but that’s not the case for double.)