Convert a string containing a hexadecimal value starting with "0x" to an integer or long

Question

How can I convert a string value like "0x310530" to an integer value in C#?

I've tried int.TryParse (and even int.TryParse with System.Globalization.NumberStyles.Any) but it does not work.

UPDATE: It seems that Convert.ToInt64 or Convert.ToInt32 work without having to remove the leading "0x":

long hwnd = Convert.ToInt64("0x310530", 16);

The documentation of Convert.ToInt64 Method (String, Int32) says:

"If fromBase is 16, you can prefix the number specified by the value parameter with "0x" or "0X"."

However, I would prefer a method like TryParse that does not raise exceptions.

Solution 1

int value = (int)new System.ComponentModel.Int32Converter().ConvertFromString("0x310530");

Solution 2

From MSDN:

NumberStyles.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. Strings that are parsed using this style cannot be prefixed with "0x" or "&h".

So you have to strip out the 0x prefix first:

string s = "0x310530";
int result;

if (s != null && s.StartsWith("0x") && int.TryParse(s.Substring(2),
                                                    NumberStyles.AllowHexSpecifier,
                                                    null,
                                                    out result))
{
    // result == 3212592
}

Solution 3

Direct from SHanselman, as pointed by Cristi Diaconescu, but I've included the main source code:

public static T GetTfromString<T>(string mystring)
{
   var foo = TypeDescriptor.GetConverter(typeof(T));
   return (T)(foo.ConvertFromInvariantString(mystring));
}

The whole article deserves a closer look!

Solution 4

If you remove the leading 0x, you could use int.Parse

int a = int.Parse("1310530", NumberStyles.AllowHexSpecifier);

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