Excel单元格列名转化成函数

   /// <summary>
   /// Excel形式的列变换
   /// </summary>
    public class ExcelCRHelper
    {
        private const string ALPHABET_UPPER = "ABCDEFGHIGKLMNOPQRSTUVWXYZ";
        /// <summary>
        /// 形如（B4）的单元格的列号提取
         /// </summary>
        /// <returns></returns>
        public static int  ExtractColIndex(string strColRow)
        {
            int iCol = -1;
            Regex reg = new Regex("[A-Z]+");
            Match m = reg.Match(strColRow);

            if (m.Success && m.Value !=null)
            {
                iCol = 0;
                if (m.Value.Length == 1)
                {
                    iCol = ALPHABET_UPPER.IndexOf(m.Value);
                }
                else if (m.Value.Length > 1)
                {
                    for (int i = 0; i < m.Value.Length; i++)
                    {
                        if (i == m.Value.Length - 1)
                        {
                            iCol += ALPHABET_UPPER.IndexOf(m.Value[i]);
                        }
                        else
                        {
                            int iBase = Convert.ToInt32( Math.Pow(26, m.Value.Length - i - 1));
                            iCol += iBase * (ALPHABET_UPPER.IndexOf(m.Value[i]) + 1);
                        }
                    }
                }
            }

            return iCol;
        }

        /// <summary>
        /// 形如（B4）的单元格的行号提取        /// </summary>
        /// <returns></returns>
        public static int ExtractRowIndex(string strColRow)
        {
            int iRow = -1;
            Regex reg = new Regex("[\\d]+");
            Match m = reg.Match(strColRow);

            if (m.Success && m.Value != null)
            {
                try
                {
                    iRow = Convert.ToInt32(m.Value) - 1;
                }
                catch
                { }
            }
            return iRow;        
        }

        /// <summary>
        /// 根据列号转换成列名（如：3-->D)
        /// </summary>
        /// <returns></returns>
        public static string GetColumnName(int colIndex)
        {
            if (colIndex < 0)
                return "";
            
            string colName = "";
            if (colIndex < 26)
            {
                colName += ALPHABET_UPPER[colIndex];
            }
            else
            {
                List<int> lstIndex = new List<int>();
                int remainder = colIndex % 26;
                colIndex = Convert.ToInt32(Math.Floor(colIndex / 26.0));
                lstIndex.Add(remainder);
                while (colIndex > 26)
                {
                    remainder = colIndex % 26;
                    colIndex = Convert.ToInt32(Math.Floor(colIndex / 26.0));
                    lstIndex.Add(remainder);
                }                

                if (colIndex > 0)
                {
                    colName += ALPHABET_UPPER[colIndex - 1];
                }
                for (int i = lstIndex.Count - 1; i >= 0; i--)
                {
                    if (i == 0)
                    {
                        colName += ALPHABET_UPPER[lstIndex[i]];
                    }
                    else
                    {
                        colName += ALPHABET_UPPER[lstIndex[i] -1];
                    }
                }
            }

            return colName;
        }
    }