Sometimes you need to parse hexadecimal strings to int values. I searched a while for the correct answer. You may use

Byte.Parse(string, NumberStyles.HexNumber);  

As always, Parse will throw an exception (ArgumentNullException, FormatException and OverflowException), if the conversion fails. There are two options of NumberStyle you may use:

AllowHexSpecifier: Indicates that the numeric string represents a hexadecimal value. Valid hexadecimal values include the numeric digits 0-9 and the hexadecimal digits A-F and a-f. Hexadecimal values can be left-padded with zeros. Strings parsed using this style are not permitted to be prefixed with "0x".

HexNumber: Indicates that the AllowLeadingWhite, AllowTrailingWhite, and AllowHexSpecifier styles are used. This is a composite number style.

There are at least two ways to convert a standard string type to an value type:

Convert.ToInt32

and

Int32.Parse

These two ways seem to be identical, but there aren’t. I used Lutz Reflector to show the differences:

Int32.Parse calls

public static int Parse(string s, NumberStyles style, IFormatProvider provider)
{
  NumberFormatInfo info1 = NumberFormatInfo.GetInstance(provider);
       NumberFormatInfo.ValidateParseStyle(style);
       return Number.ParseInt32(s, style, info1);
}

and Number.ParseInt32 is defined as InternalCall:

[MethodImpl(MethodImplOptions.InternalCall)]
public static extern int ParseInt32(
string s, NumberStyles style, NumberFormatInfo info);

Here is the code for Convert.ToInt32(string)

public static int ToInt32(string value)
{
if (value == null)
{
return 0;
}

return int.Parse(value); }

Here you see the difference: Convert checks, if the argument is null and returns 0 in this case, instead of directly throwing an exception. If you don’t need this behavior, calling Int32.Parse is a (little bit) faster than calling Convert.ToInt32. Same is true for the hundred other Xxx.Parse and Convert.Xxx calls.

In addition: we should better use int.Parse instead of int32.parse. Do you want to now the reason? Read Clemens Vasters article.