How to: Convert Between Hexadecimal Strings and Numeric Types (C# Programming Guide)

These examples show you how to perform the following tasks:

  • Obtain the hexadecimal value of each character in a string.

  • Obtain the char that corresponds to each value in a hexadecimal string.

  • Convert a hexadecimal string to an int.

  • Convert a hexadecimal string to a float.

  • Convert a byte array to a hexadecimal string.

This example outputs the hexadecimal value of each character in a string. First it parses the string to an array of characters. Then it calls ToInt32(Char) on each character to obtain its numeric value. Finally, it formats the number as its hexadecimal representation in a string.

string input = "Hello World!";
char[] values = input.ToCharArray();
foreach (char letter in values)
{
    // Get the integral value of the character. 
    int value = Convert.ToInt32(letter);
    // Convert the decimal value to a hexadecimal value in string form. 
    string hexOutput = String.Format("{0:X}", value);
    Console.WriteLine("Hexadecimal value of {0} is {1}", letter, hexOutput);
}
/* Output:
   Hexadecimal value of H is 48
    Hexadecimal value of e is 65
    Hexadecimal value of l is 6C
    Hexadecimal value of l is 6C
    Hexadecimal value of o is 6F
    Hexadecimal value of   is 20
    Hexadecimal value of W is 57
    Hexadecimal value of o is 6F
    Hexadecimal value of r is 72
    Hexadecimal value of l is 6C
    Hexadecimal value of d is 64
    Hexadecimal value of ! is 21
 */

This example parses a string of hexadecimal values and outputs the character corresponding to each hexadecimal value. First it calls the Split(Char[]) method to obtain each hexadecimal value as an individual string in an array. Then it calls ToInt32(String, Int32) to convert the hexadecimal value to a decimal value represented as an int. It shows two different ways to obtain the character corresponding to that character code. The first technique uses ConvertFromUtf32(Int32), which returns the character corresponding to the integer argument as a string. The second technique explicitly casts the int to a char.

string hexValues = "48 65 6C 6C 6F 20 57 6F 72 6C 64 21";
string[] hexValuesSplit = hexValues.Split(' ');
foreach (String hex in hexValuesSplit)
{
    // Convert the number expressed in base-16 to an integer. 
    int value = Convert.ToInt32(hex, 16);
    // Get the character corresponding to the integral value. 
    string stringValue = Char.ConvertFromUtf32(value);
    char charValue = (char)value;
    Console.WriteLine("hexadecimal value = {0}, int value = {1}, char value = {2} or {3}",
                        hex, value, stringValue, charValue);
}
/* Output:
    hexadecimal value = 48, int value = 72, char value = H or H
    hexadecimal value = 65, int value = 101, char value = e or e
    hexadecimal value = 6C, int value = 108, char value = l or l
    hexadecimal value = 6C, int value = 108, char value = l or l
    hexadecimal value = 6F, int value = 111, char value = o or o
    hexadecimal value = 20, int value = 32, char value =   or
    hexadecimal value = 57, int value = 87, char value = W or W
    hexadecimal value = 6F, int value = 111, char value = o or o
    hexadecimal value = 72, int value = 114, char value = r or r
    hexadecimal value = 6C, int value = 108, char value = l or l
    hexadecimal value = 64, int value = 100, char value = d or d
    hexadecimal value = 21, int value = 33, char value = ! or !
*/

This example shows another way to convert a hexadecimal string to an integer, by calling the Parse(String, NumberStyles) method.

string hexString = "8E2";
int num = Int32.Parse(hexString, System.Globalization.NumberStyles.HexNumber);
Console.WriteLine(num);
//Output: 2274

The following example shows how to convert a hexadecimal string to a float by using the System.BitConverter class and the Int32.Parse method.


string hexString = "43480170";
uint num = uint.Parse(hexString, System.Globalization.NumberStyles.AllowHexSpecifier);

byte[] floatVals = BitConverter.GetBytes(num);
float f = BitConverter.ToSingle(floatVals, 0);
Console.WriteLine("float convert = {0}", f);

// Output: 200.0056            

The following example shows how to convert a byte array to a hexadecimal string by using the System.BitConverter class.

byte[] vals = { 0x01, 0xAA, 0xB1, 0xDC, 0x10, 0xDD };

string str = BitConverter.ToString(vals);
Console.WriteLine(str);

str = BitConverter.ToString(vals).Replace("-", "");
Console.WriteLine(str);

/*Output:
  01-AA-B1-DC-10-DD
  01AAB1DC10DD
 */
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