Converting double to string with N decimals, dot as decimal separator, and no thousand separator

Question

I need to convert a decimal to a string with N decimals (two or four) and NO thousand separator:

\'XXXXXXX (dot) DDDDD\'

The problem with CultureInfo.I

Answer 1

double value = 3.14159D;
string v = value.ToString().Replace(",", ".");
Console.WriteLine(v);

Output: 3.14159