我非常简单的凯撒密码程序中的逻辑错误

Question

我正在尝试创建一个小项目（我是 C# 的新手），有人可以在其中输入密钥和字符串进行加密。但是我有一个逻辑错误，它没有显示。我已尽力解释每一行。

    char[] alphabet = "abcdefghijklmnopqrstuvwxyz".ToCharArray(); // so i dont have to make each thig in the array

    Console.WriteLine("KeY: "); // ask for key
    string key1 = Console.ReadLine(); // store it in a variabe
    int key = Convert.ToInt32(key1); // make it a number


    Console.WriteLine("Code to encrypt: ");

    string code = Console.ReadLine(); // strig that need to be encryot

    

    string EncryptedString = ""; // blank string to insert encrypted letter into



    int leng = code.Length;

    int i = 0;
    while (i > leng)
    {

        char x = code[i]; // x is after every loop the consequetive letter in the string that needs encrypting

        

        int y = Array.IndexOf(alphabet, x); // finds the index position that "x" is in the alphabet, e.g (a = 0, b = 1)

        int z = alphabet[y + key]; // z is the letter index of the letter in alphabet but with the key amount over , imagine the key was 2, e.g (a = c)

        string w = Convert.ToString(z); // w is z converted to a string

        EncryptedString.Insert(i - 1, w); // is the the position you want to insert the letter, w is the letter you want inserting
       



       
        
        i++;

    }

Console.WriteLine(EncryptedString);

某处出现逻辑错误，加密后的字符串不会显示