Excel列名转换

这段时间工作中需要用到Excel的列名转换，如列A，转为1或索引0，AA转为27或索引26。于是开发了个代码解决这个问题，简单记录下来。以C#代码为例：

    /// <summary>
    /// 电子表格相关转换工具
    /// </summary>
    public class ColumnConvert
    {
        /// <summary>
        /// Excel列26进制
        /// </summary>
        private static readonly int ColumnRadix = 26;

        /// <summary>
        /// 列名转数字，从1开始
        /// </summary>
        /// <param name="column">列名</param>
        /// <returns>列编号</returns>
        public static int GetColumnNumber(string column)
        {
            int res = 0;
            int power = 1;
            var col = column.ToUpper();
            for (int i = col.Length - 1; i >= 0; i--)
            {
                char now = col[i];
                int diff = now - 'A';
                res += (diff + 1) * power;
                power *= ColumnRadix;
            }

            return res;
        }

        /// <summary>
        /// 列名转索引，从0开始
        /// </summary>
        /// <param name="column">列名</param>
        /// <returns>列索引</returns>
        public static int GetColumnIndex(string column)
        {
            return GetColumnNumber(column) - 1;
        }

        /// <summary>
        /// 列号转列名，从1开始
        /// </summary>
        /// <param name="colNum">列号</param>
        /// <returns></returns>
        public static string GetColumnName(int colNum)
        {
            StringBuilder res = new StringBuilder();
            int remain = (colNum - 1) % ColumnRadix;
            char addChar = (char)('A' + remain);
            res = res.Insert(0, addChar);
            colNum = (colNum - 1) / ColumnRadix;
            while (colNum >= 1)
            {
                int left = (colNum - 1) % ColumnRadix;
                char add = (char)('A' + left);
                res = res.Insert(0, add);
                colNum = (colNum - 1) / ColumnRadix;
            }
            return res.ToString();
        }
    }