我正在使用数组来存储字符串中的字符及其对应的ASCII值。我想将字符串转换为字符。使用字符来找到asciivalue。使用这些值创建一个新字母，然后使用新字母对消息进行编码。但是我一直在获取错误变量在数组的边界之外。任何帮助都将是巨大的，我将为此而努力，并于今天到期，我无法解决。任何帮助深表感谢！
int CountKeywordLength = txtKeyword.Text.Length, i = 1, j = 1;
string KeywordStorage = txtKeyword.Text;
int[,] CharacterAsciiArray = new int[122, CountKeywordLength+1];
foreach (char ch in KeywordStorage)
{
int CharacterLetterAscii = 0, CharacterLetterAsciiPlusOne = 0 ;
string CharacterLetter = ch.ToString();
if (CharacterLetter.ToLower() == "a")
{
CharacterLetterAscii = 97;
}
else if (CharacterLetter.ToLower() == "b")
{
CharacterLetterAscii = 98;
}
else if (CharacterLetter.ToLower() == "c")
{
CharacterLetterAscii = 99;
}
else if (CharacterLetter.ToLower() == "d")
{
CharacterLetterAscii = 100;
}
else if (CharacterLetter.ToLower() == "e")
{
CharacterLetterAscii = 101;
}
else if (CharacterLetter.ToLower() == "f")
{
CharacterLetterAscii = 102;
}
else if (CharacterLetter.ToLower() == "g")
{
CharacterLetterAscii = 103;
}
else if (CharacterLetter.ToLower() == "h")
{
CharacterLetterAscii = 104;
}
else if (CharacterLetter.ToLower() == "i")
{
CharacterLetterAscii = 105;
}
else if (CharacterLetter.ToLower() == "j")
{
CharacterLetterAscii = 106;
}
else if (CharacterLetter.ToLower() == "k")
{
CharacterLetterAscii = 107;
}
else if (CharacterLetter.ToLower() == "l")
{
CharacterLetterAscii = 108;
}
else if (CharacterLetter.ToLower() == "m")
{
CharacterLetterAscii = 109;
}
else if (CharacterLetter.ToLower() == "n")
{
CharacterLetterAscii = 110;
}
else if (CharacterLetter.ToLower() == "o")
{
CharacterLetterAscii = 111;
}
else if (CharacterLetter.ToLower() == "p")
{
CharacterLetterAscii = 112;
}
else if (CharacterLetter.ToLower() == "q")
{
CharacterLetterAscii = 113;
}
else if (CharacterLetter.ToLower() == "r")
{
CharacterLetterAscii = 114;
}
else if (CharacterLetter.ToLower() == "s")
{
CharacterLetterAscii = 115;
}
else if (CharacterLetter.ToLower() == "t")
{
CharacterLetterAscii = 116;
}
else if (CharacterLetter.ToLower() == "u")
{
CharacterLetterAscii = 117;
}
else if (CharacterLetter.ToLower() == "v")
{
CharacterLetterAscii = 118;
}
else if (CharacterLetter.ToLower() == "w")
{
CharacterLetterAscii = 119;
}
else if (CharacterLetter.ToLower() == "x")
{
CharacterLetterAscii = 120;
}
else if (CharacterLetter.ToLower() == "y")
{
CharacterLetterAscii = 121;
}
else if (CharacterLetter.ToLower() == "z")
{
CharacterLetterAscii = 122;
}
CharacterAsciiArray[i,j] = CharacterLetterAscii;
CharacterLetterAsciiPlusOne = CharacterLetterAscii + 1;
i++;
for (i = 2; i < 24; i++)
{
CharacterAsciiArray[i, j] = CharacterLetterAsciiPlusOne;
CharacterLetterAsciiPlusOne++;
if (CharacterLetterAsciiPlusOne > 122)
{
int DifferenceCharacterAscii = CharacterLetterAsciiPlusOne - 122;
CharacterLetterAsciiPlusOne = 65 + DifferenceCharacterAscii;
i++;
}
}
j++;
}
string MessageCharacters = txtEncryption.Text;
int MessageLetterAscii = 0;
int CountMessageLength = txtEncryption.Text.Length;
int[] MessageAsciiArray = new int[CountMessageLength+1];
foreach (char c in MessageCharacters)
{
string MessageCharactersStore = c.ToString();
if (MessageCharactersStore.ToLower() == "a")
{
MessageLetterAscii = 97;
}
else if (MessageCharactersStore.ToLower() == "b")
{
MessageLetterAscii = 98;
}
else if (MessageCharactersStore.ToLower() == "c")
{
MessageLetterAscii = 99;
}
else if (MessageCharactersStore.ToLower() == "d")
{
MessageLetterAscii = 100;
}
else if (MessageCharactersStore.ToLower() == "e")
{
MessageLetterAscii = 101;
}
else if (MessageCharactersStore.ToLower() == "f")
{
MessageLetterAscii = 102;
}
else if (MessageCharactersStore.ToLower() == "g")
{
MessageLetterAscii = 103;
}
else if (MessageCharactersStore.ToLower() == "h")
{
MessageLetterAscii = 104;
}
else if (MessageCharactersStore.ToLower() == "i")
{
MessageLetterAscii = 105;
}
else if (MessageCharactersStore.ToLower() == "j")
{
MessageLetterAscii = 106;
}
else if (MessageCharactersStore.ToLower() == "k")
{
MessageLetterAscii = 107;
}
else if (MessageCharactersStore.ToLower() == "l")
{
MessageLetterAscii = 108;
}
else if (MessageCharactersStore.ToLower() == "m")
{
MessageLetterAscii = 109;
}
else if (MessageCharactersStore.ToLower() == "n")
{
MessageLetterAscii = 110;
}
else if (MessageCharactersStore.ToLower() == "o")
{
MessageLetterAscii = 111;
}
else if (MessageCharactersStore.ToLower() == "p")
{
MessageLetterAscii = 112;
}
else if (MessageCharactersStore.ToLower() == "q")
{
MessageLetterAscii = 113;
}
else if (MessageCharactersStore.ToLower() == "r")
{
MessageLetterAscii = 114;
}
else if (MessageCharactersStore.ToLower() == "s")
{
MessageLetterAscii = 115;
}
else if (MessageCharactersStore.ToLower() == "t")
{
MessageLetterAscii = 116;
}
else if (MessageCharactersStore.ToLower() == "u")
{
MessageLetterAscii = 117;
}
else if (MessageCharactersStore.ToLower() == "v")
{
MessageLetterAscii = 118;
}
else if (MessageCharactersStore.ToLower() == "w")
{
MessageLetterAscii = 119;
}
else if (MessageCharactersStore.ToLower() == "x")
{
MessageLetterAscii = 120;
}
else if (MessageCharactersStore.ToLower() == "y")
{
MessageLetterAscii = 121;
}
else if (MessageCharactersStore.ToLower() == "z")
{
MessageLetterAscii = 122;
}
int DifferenceCalculation = MessageLetterAscii - 97;
int MessageAsciiValue = CharacterAsciiArray[1,j];
if (DifferenceCalculation > 0)
{
MessageAsciiValue = CharacterAsciiArray[1, j] + DifferenceCalculation;
}
MessageAsciiArray[i] = MessageAsciiValue;
i++;
j++;
if (j > 3)
{
j = 1;
}
}
string[] MessageArray = new string[122];
for ( i = 1; i < CountMessageLength; i++)
{
if (MessageAsciiArray[i] == 97)
{
MessageArray[i] = "a";
}
else if (MessageAsciiArray[i] == 98)
{
MessageArray[i] = "b";
}
else if (MessageAsciiArray[i] == 99)
{
MessageArray[i] = "c";
}
else if (MessageAsciiArray[i] == 100)
{
MessageArray[i] = "d";
}
else if (MessageAsciiArray[i] == 101)
{
MessageArray[i] = "e";
}
else if (MessageAsciiArray[i] == 102)
{
MessageArray[i] = "f";
}
else if (MessageAsciiArray[i] == 103)
{
MessageArray[i] = "g";
}
else if (MessageAsciiArray[i] == 104)
{
MessageArray[i] = "h";
}
else if (MessageAsciiArray[i] == 105)
{
MessageArray[i] = "i";
}
else if (MessageAsciiArray[i] == 106)
{
MessageArray[i] = "j";
}
else if (MessageAsciiArray[i] == 107)
{
MessageArray[i] = "k";
}
else if (MessageAsciiArray[i] == 108)
{
MessageArray[i] = "l";
}
else if (MessageAsciiArray[i] == 109)
{
MessageArray[i] = "m";
}
else if (MessageAsciiArray[i] == 110)
{
MessageArray[i] = "n";
}
else if (MessageAsciiArray[i] == 111)
{
MessageArray[i] = "o";
}
else if (MessageAsciiArray[i] == 112)
{
MessageArray[i] = "p";
}
else if (MessageAsciiArray[i] == 113)
{
MessageArray[i] = "q";
}
else if (MessageAsciiArray[i] == 114)
{
MessageArray[i] = "r";
}
else if (MessageAsciiArray[i] == 115)
{
MessageArray[i] = "s";
}
else if (MessageAsciiArray[i] == 116)
{
MessageArray[i]= "t";
}
else if (MessageAsciiArray[i] == 117)
{
MessageArray[i] = "u";
}
else if (MessageAsciiArray[i] == 118)
{
MessageArray[i] = "v";
}
else if (MessageAsciiArray[i] == 119)
{
MessageArray[i] = "w";
}
else if (MessageAsciiArray[i] == 120)
{
MessageArray[i] = "x";
}
else if (MessageAsciiArray[i] == 121)
{
MessageArray[i] = "y";
}
else if (MessageAsciiArray[i] == 122)
{
MessageArray[i] = "z";
}
i++;