字符串工具类

using System;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace DataSync
{
    public class WordHelper
    {
        [DllImport("kernel32.dll", EntryPoint = "LCMapStringA")]
        public static extern int LCMapString(int locale, int dwMapFlags, byte[] lpSrcStr, int cchSrc, byte[] lpDestStr, int cchDest);
        //转为繁体
        public static string ToTraditionalChinese(string source)
        {
            return ToTraditional(source, 0x04000000);
        }
        //转为简体
        public static string ToSimplifiedChinese(string source)
        {
            return ToTraditional(source, 0x02000000);
        }
        public static string ToTraditional(string source, int type)
        {
            byte[] srcByte = Encoding.Default.GetBytes(source);
            byte[] desByte = new byte[srcByte.Length];
            LCMapString(2052, type, srcByte, -1, desByte, srcByte.Length);
            string des = Encoding.Default.GetString(desByte);
            return des;
        }
        //判定这个词语是否是汉字
        //汉字区间 0x4e00 0x9fbb
        public static bool IsChinese(string word)
        {
            char[] chars = word.ToCharArray();
            foreach (var c in chars)
            {
                if (!(c >= 0x4e00 && c <= 0x9fbb))
                    return false;
            }
            return true;
        }
        public static string Substring(string text, int maxLength)
        {
            if (string.IsNullOrEmpty(text))
                return string.Empty;
            StringBuilder stringBuilder = new StringBuilder();
            bool surrogate;
            int index = 0;
            int count = 0;
            foreach (char item in text)
            {
                if (index >= maxLength)
                    break;
                //防止截断表情
                surrogate = char.IsSurrogate(item);
                if (surrogate)
                {
                    count++;
                    if (count > 1)
                        count = 0;
                }
                stringBuilder.Append(item);
                index++;
            }
            if (count == 1)
            {
                char lastChar = text[index++];
                stringBuilder.Append(lastChar);
            }
            return stringBuilder.ToString();
        }
    }
}