If your final aim is to send byte[], then you can actually skip the middle step and immediately do the conversion from string to byte[] using Encoding.ASCII.GetBytes (provided that you send ASCII char):
string beforeConverting = "HELLO";
byte[] byteData = Encoding.ASCII.GetBytes(beforeConverting);
//will give you {0x48, 0x45, 0x4C, 0x4C, 0x4F};
If you don't send ASCII, you could find the appropriate Encoding type (like Unicode or UTF32), depends on your need.
That being said, if you still want to convert the hex string to byte array, you could do something something like this:
/// <summary>
/// To convert Hex data string to bytes (i.e. 0x01455687) given the data type
/// </summary>
/// <param name="hexString"></param>
/// <param name="dataType"></param>
/// <returns></returns>
public static byte[] HexStringToBytes(string hexString) {
try {
if (hexString.Length >= 3) //must have minimum of length of 3
if (hexString[0] == '0' && (hexString[1] == 'x' || hexString[1] == 'X'))
hexString = hexString.Substring(2);
int dataSize = (hexString.Length - 1) / 2;
int expectedStringLength = 2 * dataSize;
while (hexString.Length < expectedStringLength)
hexString = "0" + hexString; //zero padding in the front
int NumberChars = hexString.Length / 2;
byte[] bytes = new byte[NumberChars];
using (var sr = new StringReader(hexString)) {
for (int i = 0; i < NumberChars; i++)
bytes[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);
}
return bytes;
} catch {
return null;
}
}
And then use it like this:
byte[] byteData = afterConverting.Select(x => HexStringToBytes(x)[0]).ToArray();
The method I put above is more general which can handle input string like 0x05163782 to give byte[4]. For your use, you only need to take the first byte (as the byte[] will always be byte[1]) and thus you have [0] index in the LINQ Select.
The core method used in the custom method above is Convert.ToByte():
bytes[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);
