Remove trailing zeros

I use this code to avoid "G29" scientific notation:

public static string DecimalToString(this decimal dec)
{
    string strdec = dec.ToString(CultureInfo.InvariantCulture);
    return strdec.Contains(".") ? strdec.TrimEnd('0').TrimEnd('.') : strdec;
}

EDIT: using system CultureInfo.NumberFormat.NumberDecimalSeparator :

public static string DecimalToString(this decimal dec)
{
    string sep = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator;
    string strdec = dec.ToString(CultureInfo.CurrentCulture);
    return strdec.Contains(sep) ? strdec.TrimEnd('0').TrimEnd(sep.ToCharArray()) : strdec;
}

In my opinion its safer to use Custom Numeric Format Strings.

decimal d = 0.00000000000010000000000m;
string custom = d.ToString("0.#########################");
// gives: 0,0000000000001
string general = d.ToString("G29");
// gives: 1E-13

Is it not as simple as this, if the input IS a string? You can use one of these:

string.Format("{0:G29}", decimal.Parse("2.0044"))

decimal.Parse("2.0044").ToString("G29")

2.0m.ToString("G29")

This should work for all input.

Update Check out the Standard Numeric Formats I've had to explicitly set the precision specifier to 29 as the docs clearly state:

However, if the number is a Decimal and the precision specifier is omitted, fixed-point notation is always used and trailing zeros are preserved

Update Konrad pointed out in the comments:

Watch out for values like 0.000001. G29 format will present them in the shortest possible way so it will switch to the exponential notation. string.Format("{0:G29}", decimal.Parse("0.00000001",System.Globalization.CultureInfo.GetCultureInfo("en-US"))) will give "1E-08" as the result.

I ran into the same problem but in a case where I do not have control of the output to string, which was taken care of by a library. After looking into details in the implementation of the Decimal type (see http://msdn.microsoft.com/en-us/library/system.decimal.getbits.aspx), I came up with a neat trick (here as an extension method):

public static decimal Normalize(this decimal value)
{
    return value/1.000000000000000000000000000000000m;
}

The exponent part of the decimal is reduced to just what is needed. Calling ToString() on the output decimal will write the number without any trailing 0. E.g.

1.200m.Normalize().ToString();