中英混排做字符串精确截取

   private ArrayList GetSeparateSubString(string mOrigianlString, int subStringCharNumber)
        {
            ArrayList resultList = new ArrayList(); 
            string tempStr = mOrigianlString; 
            int charNumber = subStringCharNumber; 
            int totalCount = 0; 
            string mSubStr = ""; 
            for (int i = 0; i < tempStr.Length; i++)
            {
                string mChar = tempStr.Substring(i, 1); 
                int byteCount = Encoding.Default.GetByteCount(mChar);
                //关键点判断字符所占的字节数   
                if (byteCount == 1) 
                { 
                    totalCount++; 
                    mSubStr += mChar; 
                    if (totalCount == charNumber || i == tempStr.Length - 1) 
                    { 
                        resultList.Add(mSubStr); 
                        totalCount = 0; 
                        mSubStr = ""; 
                    } 
                } else if (byteCount > 1) 
                { 
                    totalCount += 2;
                    if (totalCount > charNumber) 
                    {
                        resultList.Add(mSubStr); 
                        if (i == tempStr.Length - 1) 
                        { 
                            mSubStr = mChar;
                            resultList.Add(mSubStr); 
                        } else { 
                            totalCount = 2; 
                            mSubStr = mChar; 
                        }
                    } else if (totalCount == charNumber) 
                    { 
                        mSubStr += mChar; 
                        resultList.Add(mSubStr);
                        totalCount = 0;
                        mSubStr = ""; 
                    } else if (i == tempStr.Length - 1) {
                        mSubStr += mChar; 
                        resultList.Add(mSubStr);
                    } else {
                        mSubStr += mChar; 
                    } 
                }
            } return resultList;
        }