i am receiving bytes from the serial port on my c# , and i am storing them in a byte array and then making them as string so now i need to convert the bytes to ASCII how i can do that? This is my code
void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e) {
    string bytestr = "";
    int numbytes = serialPort1.BytesToRead;
    byte[] rxbytearray = new byte[numbytes];
    for (int i = 0; i < numbytes; i++)
    {
        rxbytearray[i] = (byte)serialPort1.ReadByte();
    }
    string hexvalues = "";
    foreach (byte b in rxbytearray)
    {
        if (b != '\r')
            hexvalues = hexvalues + (b.ToString()) + " ";
    }       //  hexvalues = richTextBox1.Text;
    Thread.Sleep(500);
    MessageBox.Show(hexvalues);
}