00003232 00002132-00000545 00646545-00000465

[Test()]
    public void TestNegativePadding()
    {
        int number1 = 123;
        int number2 = -123;
        Assert.AreEqual(" 00000123", string.Format("{0,9:D8}", number1));
        Assert.AreEqual("-00000123", string.Format("{0,9:D8}", number2));

        string str = "";
        int[] test = {3232, 2132, -545, 646545, -465};
        foreach (var number in test)
        {
            str += string.Format("{0,9:D8}", number);
        }
        Assert.AreEqual("00003232 00002132-00000545 00646545-00000465", str.Trim());
    }

byte byteValue = 254;
short shortValue = 10342;
int intValue = 1023983;
long lngValue = 6985321;
ulong ulngValue = UInt64.MaxValue;

// Display integer values by caling the ToString method.
Console.WriteLine("{0,22} {1,22}", byteValue.ToString("D8"), byteValue.ToString("X8"));
Console.WriteLine("{0,22} {1,22}", shortValue.ToString("D8"), shortValue.ToString("X8"));
Console.WriteLine("{0,22} {1,22}", intValue.ToString("D8"), intValue.ToString("X8"));
Console.WriteLine("{0,22} {1,22}", lngValue.ToString("D8"), lngValue.ToString("X8"));
Console.WriteLine("{0,22} {1,22}", ulngValue.ToString("D8"), ulngValue.ToString("X8"));
Console.WriteLine();

// Display the same integer values by using composite formatting.
Console.WriteLine("{0,22:D8} {0,22:X8}", byteValue);
Console.WriteLine("{0,22:D8} {0,22:X8}", shortValue);
Console.WriteLine("{0,22:D8} {0,22:X8}", intValue);
Console.WriteLine("{0,22:D8} {0,22:X8}", lngValue);
Console.WriteLine("{0,22:D8} {0,22:X8}", ulngValue);
// The example displays the following output:
//                     00000254               000000FE
//                     00010342               00002866
//                     01023983               000F9FEF
//                     06985321               006A9669
//         18446744073709551615       FFFFFFFFFFFFFFFF
//
//                     00000254               000000FE
//                     00010342               00002866
//                     01023983               000F9FEF
//                     06985321               006A9669
//         18446744073709551615       FFFFFFFFFFFFFFFF
//         18446744073709551615       FFFFFFFFFFFFFFFF

var result = string.Join("",  new []{ 1,2,3,4,5,-5,-8 }
   .Select((i, y) => (i >= 0 && y > 0 ? " " : "") + string.Format("{0:D8}", i)));

00000001 00000002 00000003 00000004 00000005-00000005-00000008