public static void Main()
string format = "{0, -40} {1, -15}";
object [] values = { "-128" , "-89","ABC", "true", "12/31/2018", "a", ".", "546565255465", "10888", "5465665", "4/2/2007 7:23:57 PM -07:00"};
Console.WriteLine(format, "Object", "Is Valid String");
Console.WriteLine(format, "------", "---------------");
foreach(var val in values)
Console.WriteLine(format, val, val.IsValidString());