Question

I have this program that is reading the test string from a textbox and convert it to a byte array that makeup data to be diplayed on a screen. I am getting very close. The code can currently pull the text, convert it to a char array, and then replace the zeros in the byte array with useful data from a 2 dimensional array that contains 5 bits for all the letters of the alphabet. I am have a problem though. The code only seems to run once. If I click the button a second time I end up with an “indexOutOfRange exception unhandled.” Also it only seems to work for one letter at a time

EX: if I type “A” it will display, but if I type “AA” I get the same error.
Here is the WordArray[]

byte[,] Letters = new byte[18, 5] { { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 },
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 },
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 }, 
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 }, 
                                       { 63, 72, 72, 63, 0 }, 
                                       { 127, 73, 73, 54, 0 },
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 },
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 }, 
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 },
                                       { 63, 72, 72, 63, 0 },
                                       { 127, 73, 73, 54, 0 } };

Here is the click_button method:

    int Aindex = 0;
    int LettersIndex = 0;
    private void SendButton_Click(object sender, EventArgs e)
    {
        WordIndex = 0;
        if (Aindex > 0)
        {
            Aindex = 0;
        }
        string CurrentTextString = textBox1.Text;
        char[] charArray = CurrentTextString.ToCharArray();
        if (textBox1.Text == "")
        {

        }
        else
        {
            foreach (char c in charArray)
            {
                int index = 0;
                CharAsciiArray[index] = Convert.ToChar((Convert.ToInt32(c)));
                textBox2.Text += CharAsciiArray[index] + " ";
                charCount++;
                index++;
            }
            for (int NumberofBytes = 0; NumberofBytes < charCount; NumberofBytes++)
            {

                LettersIndex = 0;
                // int currentChar = CharAsciiArray[index] - 65;
                //textBox2.Text += currentChar;
                int currentCharAscii = (CharAsciiArray[Aindex]);
                int currentChar = currentCharAscii - 'A';
                for (int NumberofBits = 0; NumberofBits < 5; NumberofBits++)
                {


                    // textBox2.Text += currentChar;
                    WordArray[WordIndex + 3] = Letters[currentChar, LettersIndex];
                    textBox2.Text += WordArray[WordIndex] + " ";
                    LettersIndex++;
                    WordIndex++;
                }
                Aindex++;
            }
            SendingData = true;
            //SendNextByte();

            serialPort1.Write(WordArray, 0, WordArray.Length);
        }
    }

Answer 1

In the following loop

  foreach (char c in charArray)
  {
      int index = 0;
      CharAsciiArray[index] = Convert.ToChar((Convert.ToInt32(c)));
      textBox2.Text += CharAsciiArray[index] + " ";
      charCount++;
      index++;
  }

You apparently want to increase the index on each iteration but you’re resetting index to 0 every time.

Besides that, make up your mind on what pattern you want to follow when naming your variables. For instance:

Why is AIndex not AnIndex and how would you name the next index? AnotherIndex? Does it need to be global? Why does charArray start with a lowercase c and NumberOfBytes with an uppercase N? Write code as if you would have to explain it to your wife / husband (who knows?) and it’ll be easier to maintain / debug.