Generating an array of letters in the alphabet

I don't think there is a built in way, but I think the easiest would be

  char[] alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

C# 3.0 :

char[] az = Enumerable.Range('a', 'z' - 'a' + 1).Select(i => (Char)i).ToArray();
foreach (var c in az)
{
    Console.WriteLine(c);
}

yes it does work even if the only overload of Enumerable.Range accepts int parameters ;-)

for (char letter = 'A'; letter <= 'Z'; letter++)
{
     Debug.WriteLine(letter);
}

char[] alphabet = Enumerable.Range('A', 26).Select(x => (char)x).ToArray();

I wrote this to get the MS excel column code (A,B,C, ..., Z, AA, AB, ..., ZZ, AAA, AAB, ...) based on a 1-based index. (Of course, switching to zero-based is simply leaving off the column--; at the start.)

public static String getColumnNameFromIndex(int column)
{
    column--;
    String col = Convert.ToString((char)('A' + (column % 26)));
    while (column >= 26)
    {
        column = (column / 26) -1;
        col = Convert.ToString((char)('A' + (column % 26))) + col;
    }
    return col;
}