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c#stringbytexor

Converting from string to byte

I have a string which is 40FA. I would like to perform an XOR operation to it and return a byte which is 0xBA in this case. However, I'm only able to get that BA in string. When I convert BA to byte, I'm getting 186. 

string tmp = "40FA";
int uid_1 = Convert.ToInt32(tmp.Substring(0, 2), 16);
int uid_2 = Convert.ToInt32(tmp.Substring(2, 2), 16);

int test = uid_1 ^ uid_2 ;
string final = test.ToString("X");
byte byteresult = Byte.Parse(final , NumberStyles.HexNumber);
Solution

  • I think there is a little misunderstanding here. You actually already solved your problem. The computer does not care whether the number is decimal or hexadecimal or octadecimal or binary. These are just representations of a number. So only you care how it is to be displayed.

    As DmitryBychenko already said: 0xBA is the same number as 186. It won't matter for your byte array if you want to store it there. It only matters for you as a user if you want to display it.

    EDIT: you can test it by running this line of code:

    Console.WriteLine((byteresult == Convert.ToInt32("BA", 16)).ToString());

    Your code actually does what you want if I understood you correctly from your comments.

    string tmp = "40FA";
int uid_1 = Convert.ToInt32(tmp.Substring(0, 2), 16);
int uid_2 = Convert.ToInt32(tmp.Substring(2, 2), 16);

int test = uid_1 ^ uid_2 ;
string final = test.ToString("X");

// here you actually have achieved what you wanted.
byte byteresult = Byte.Parse(final , NumberStyles.HexNumber);

    now you can use byteresult to store it in a byte[], and this:

    byte[] MyByteArray = new byte[4];
MyByteArray [0] = byteresult;

    should execute without problems.