Question

var numberFormat = new NumberFormatInfo();
numberFormat.NumberDecimalSeparator = ".";
numberFormat.NumberDecimalDigits = 2;

decimal a = 10.00M;
decimal b = 10M;

Console.WriteLine(a.ToString(numberFormat));
Console.WriteLine(b.ToString(numberFormat));
Console.WriteLine(a == b ? "True": "False");

In console:
10.00
10
True

Why is it different? More important, how do I call ToString() to ensure same output no matter how a variable is initialized?

Answer 1

The NumberDecimalDigits property is used with the "F" and "N" standard format strings, not the ToString method called without a format string.

You can use:

Console.WriteLine(a.ToString("N", numberFormat));