c# - 数字转换为汉字

public static string Convert2Chinese(int input)
        {
            string ret = null;
            int input2 = Math.Abs(input);
            string resource = "零一二三四五六七八九";
            string unit = "个十百千万亿兆京垓秭穰沟涧正载极";
            if (input > Math.Pow(10, 4 * (unit.Length - unit.IndexOf('万'))))
            {
                throw new System.Exception("the input is too big,input:" + input);
            }
            Func<int, List<List<int>>> splitNumFunc = (val) => {
                int i = 0;
                int mod;
                int val_ = val;
                List<List<int>> splits = new List<List<int>>();
                List<int> splitNums;
                do
                {
                    mod = val_ % 10;
                    val_ /= 10;
                    if (i % 4 == 0)
                    {
                        splitNums = new List<int>();
                        splitNums.Add(mod);
                        if (splits.Count == 0)
                        {
                            splits.Add(splitNums);
                        }
                        else
                        {
                            splits.Insert(0, splitNums);
                        }
                    }
                    else
                    {
                        splitNums = splits[0];
                        splitNums.Insert(0, mod);
                    }
                    i++;
                } while (val_ > 0);
                return splits;
            };

            Func<List<List<int>>, string> hommizationFunc = (data) => {
                List<StringBuilder> builders = new List<StringBuilder>();
                for (int i = 0; i < data.Count; i++)
                {
                    List<int> data2 = data[i];
                    StringBuilder newVal = new StringBuilder();
                    for (int j = 0; j < data2.Count;)
                    {
                        if (data2[j] == 0)
                        {
                            int k = j + 1;
                            for (; k < data2.Count && data2[k] == 0; k++) ;
                            //个位不是0，前面补一个零
                            newVal.Append('零');
                            j = k;
                        }
                        else
                        {
                            newVal.Append(resource[data2[j]]).Append(unit[data2.Count - 1 - j]);
                            j++;
                        }
                    }
                    if (newVal[newVal.Length - 1] == '零' && newVal.Length > 1)
                    {
                        newVal.Remove(newVal.Length - 1, 1);
                    }
                    else if (newVal[newVal.Length - 1] == '个')
                    {
                        newVal.Remove(newVal.Length - 1, 1);
                    }

                    if (i == 0 && newVal.Length > 1 && newVal[0] == '一' && newVal[1] == '十')
                    {//一十 --> 十
                        newVal.Remove(0, 1);
                    }
                    builders.Add(newVal);
                }
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < builders.Count; i++)
                {//拼接
                    if (builders.Count == 1)
                    {//个位数
                        sb.Append(builders[i]);
                    }
                    else
                    {
                        if (i == builders.Count - 1)
                        {//万位以下的
                            if (builders[i][builders[i].Length - 1] != '零')
                            {//十位以上的不拼接"零"
                                sb.Append(builders[i]);
                            }
                        }
                        else
                        {//万位以上的
                            if (builders[i][0] != '零')
                            {//零万零亿之类的不拼接
                                sb.Append(builders[i]).Append(unit[unit.IndexOf('千') + builders.Count - 1 - i]);
                            }
                        }
                    }
                }
                return sb.ToString();
            };
            List<List<int>> ret_split = splitNumFunc(input2);
            ret = hommizationFunc(ret_split);
            if (input < 0) ret = "-" + ret;
            return ret;
        }