How to create byte array with your own bytes?

Question

I have to create my own byte array e.g:

byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, 0x07 };

This byte array works fine, but I need to change some hex code. I tried to do a lot of changes but no one work.

Int32 hex = 0xA1; 

byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, hex};


string hex = "0xA1"; 

byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, hex};


byte[] array = new byte[1];
array[0] = 0xA1;

byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, array[0]};

I don't know what type of variable I must have to use to replace automatic the array values.

Answer 1

Cast your int to byte:

Int32 hex = 0xA1; 
byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, (byte)hex};

Or define it as byte to begin with:

byte hex = 0xA1; 
byte[] connect = new byte[] { 0x00, 0x21, 0x60, 0x1F, 0xA1, hex};

String to byte conversion:

static byte hexstr2byte(string s)
{
    if (!s.StartsWith("0x") || s.Length != 4)
        throw new FormatException();
    return byte.Parse(s.Substring(2), System.Globalization.NumberStyles.HexNumber);
}

As you can see, .NET formatting supports hexa digits, but not the "0x" prefix. It would be easier to omit that part altogether, but your question isn't exactly clear about that.

Answer 2

Declare it like "byte hex = 0xA1" maybe?

Answer 3

On a WinCE5 system I had to pass a char-string from a C# app to a c-dll. To form up the char string in the c# code I had to cast to byte (like @fejesjoco suggested). So to form the string test_ I had byte[] name_comms_layer = new byte[] {(byte)0x74,(byte) 0x65,(byte)0x73,(byte)0x74,(byte)0x5f,(byte) 0x00} //test_ Painful but it did work.