Excel列名序号互转

public static int ToIndex(string columnName)
{
    if (!Regex.IsMatch(columnName.ToUpper(), @"[A-Z]+")) { throw new Exception("invalid parameter"); }

    int index = ;
    char[] chars = columnName.ToUpper().ToCharArray();
    for (int i = ; i < chars.Length; i++)
    {
        index += ((int)chars[i] - (int)'A' + ) * (int)Math.Pow(, chars.Length - i - );
    }
    return index - ;
}

public static string ToName(int index)
{
    if (index < ) { throw new Exception("invalid parameter"); }

    List<string> chars = new List<string>();
    do
    {
        if (chars.Count > ) index--;
        chars.Insert(, ((char)(index %  + (int)'A')).ToString());
        index = (int)((index - index % ) / );
    } while (index > );

    return String.Join(string.Empty, chars.ToArray());
}

转自：https://www.cnblogs.com/lhlong/p/7920408.html