C#中常用的字符串处理函数

C#中常用的字符串处理函数，仅供参考

/*=============================================================
 * 常用的字符串处理
 * Author ： Danny,Li
 * E-mail ： xing.dong.li@163.com
 * Edition： V-101014
 *=============================================================*/
using System;
using System.Collections.Generic;
using System.Text;

namespace IRCommon
{
    public class StringHelper
    {
        //键盘信息串(用于字符串加密)
        static string pwdstrs = ":3!@XSK#$GyTuVB%2^&C*t(dfD)_+?rFHJs6/>4iop9A5LZ 8a.<,{zUIxc}[]'|ERY\\10qwPeg7hjklNMv=-bnm~`QWO";

        /// <summary>
        /// 私有构造方法，不允许创建实例
        /// </summary>
        private StringHelper()
        {
            // TODO: Add constructor logic here
        }

        /// <summary>
        /// 从字符串左边截取指定字符个数的子串
        /// </summary>
        /// <param name="argString">欲截取的字符串</param>
        /// <param name="argLength">指定截取字符个数</param>
        /// <returns>截取后的相应字串/空串</returns>
        public static string GetLeftString(string argString, int argLength)
        {
            if (argString == null || argString.Length == 0)
                return String.Empty;

            if (argLength <= 0 || argLength > argString.Length)
                return String.Empty;

            return argString.Substring(0, argLength);
        }

        /// <summary>
        /// 从字符串右边截取指定字符个数的字串
        /// </summary>
        /// <param name="argString">欲截取的字符串</param>
        /// <param name="argLength">指定截取字符个数</param>
        /// <returns>截取后的相应字串/空串</returns>
        public static string GetRightString(string argString, int argLength)
        {
            if (argString == null || argString.Length == 0)
                return String.Empty;

            if (argLength <= 0 || argLength > argString.Length)
                return String.Empty;

            return argString.Substring(argString.Length - argLength, argLength);
        }

        /// <summary>
        /// 获得指定字符串的字节长度
        /// </summary>
        /// <param name="argString">指定的字符串</param>
        /// <returns>指定字符串的字节长度（英文字母为1个字节，汉字为2个字节）</returns>
        public static int GetStringByteLength(string argString)
        {
            if (argString == null || argString.Length == 0)
                return 0;

            byte[] bytes = Encoding.Default.GetBytes(argString);
            return bytes.Length;
        }

        /// <summary>
        /// 从字符串左边截取指定字节数的子串
        /// </summary>
        /// <param name="argString">欲截取的字符串</param>
        /// <param name="argLength">指定的字节数</param>
        /// <returns>截取后的相应字串/空串</returns>
        public static string GetLeftStringByte(string argString, int argLength)
        {
            if (argString == null || argString.Length == 0 || argLength <= 0)
                return String.Empty;

            if (argLength > GetStringByteLength(argString))
                return argString;

            int i = argString.Length;
            while (GetStringByteLength(GetLeftString(argString, i)) > argLength)
            {
                i = i - 1;
            }
            return GetLeftString(argString, i);

        }

        /// <summary>
        /// 判断字符串是否为空
        /// </summary>
        /// <param name="argText">欲判断的字符串</param>
        /// <returns>为空返回True，不为空返回False</returns>
        public static bool IsEmpty(string argString)
        {
            if (argString == null || argString.Trim().Length == 0)
                return true;
            return false;
        }

        /// <summary>
        /// 获得某个特定字符在指定字符串中出现的次数
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <param name="argChar">特定字符</param>
        /// <returns>出现的次数</returns>
        public static int GetDisplayCount(string argString, char argChar)
        {
            if (argString == null || argString.Length == 0)
                return 0;

            int count = 0;
            int currentPos = 0;
            while (true)
            {
                currentPos = argString.IndexOf(argChar, currentPos) + 1;
                if (currentPos == 0)
                    break;
                else
                    count = count + 1;
            }
            return count;
        }

        /// <summary>
        /// 获得某个特定字符串在指定字符串中出现的次数
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <param name="argDestString">特定字符串</param>
        /// <returns>出现次数</returns>
        public static int GetDisplayCount(string argString, string argDestString)
        {
            if (argString == null || argString.Length == 0 ||
                argDestString == null || argDestString.Length == 0)
                return 0;
            int count = 0;
            int currentPos = 0;
            while (true)
            {
                currentPos = argString.IndexOf(argDestString, currentPos) + argDestString.Length;
                if (currentPos == argDestString.Length - 1)
                    break;
                else
                    count = count + 1;
            }
            return count;
        }

        /// <summary>
        /// 判断指定的字符串是否是整数
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <returns>是整数返回True，不是整数返回False</returns>
        public static bool IsInteger(string argString)
        {
            if (IsEmpty(argString))
                return false;

            try
            {
                int.Parse(argString);
                return true;
            }
            catch (Exception)
            {
                return false;
            }
        }

        /// <summary>
        /// 判断指定字符串是否全为数字
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <returns>全为数字返回True，不全为数字返回False</returns>
        public static bool IsNumeric(string argString)
        {
            if (IsEmpty(argString))
                return false;

            char[] chars = argString.ToCharArray();
            for (int i = 0; i < chars.Length; i++)
            {
                if (chars[i] < '0' || chars[i] > '9')
                    return false;
            }
            return true;
        }

        /// <summary>
        /// 判断指定的字符串是否为数值
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <returns>是数值返回True，不是数值返回False</returns>
        public static bool IsDigital(string argString)
        {
            if (IsEmpty(argString))
                return false;
            try
            {
                decimal.Parse(argString);
                return true;
            }
            catch (Exception)
            {
                return false;
            }
        }

        /// <summary>
        /// 判断指定字符串是否为日期
        /// </summary>
        /// <param name="argString">指定字符串</param>
        /// <returns>是日期返回True，不是日期返回False</returns>
        public static bool IsDateTime(string argString)
        {
            if (IsEmpty(argString))
                return false;

            try
            {
                DateTime.Parse(argString);
                return true;
            }
            catch (Exception)
            {
                return false;
            }

        }

        /// <summary>
        /// 格式化指定数值的小数位数
        /// </summary>
        /// <param name="argDecimal">指定的数值</param>
        /// <param name="argDecimalDigits">保留小数位数</param>
        /// <returns>格式化后的数值字符串</returns>
        public static string GetFormatDigital(decimal argDecimal, int argDecimalDigits)
        {
            string text = argDecimal.ToString();
            string format = new string('#', text.Length - 1) + "0." + new string('0', argDecimalDigits);
            return argDecimal.ToString(format);
        }

        /// <summary>
        /// 格式化指定数值为货币表达
        /// </summary>
        /// <param name="argDecimal">指定数值</param>
        /// <returns>格式化后的货币表达</returns>
        public static string GetCurrency(decimal argDecimal)
        {
            string sDecimal = argDecimal.ToString();
            //分拆
            string reghtText = null;
            string leftText = null;
            int dotPos = sDecimal.IndexOf('.');
            if (dotPos == -1)
            {
                leftText = sDecimal;
                reghtText = string.Empty;
            }
            else
            {
                leftText = sDecimal.Substring(0, dotPos);
                reghtText = sDecimal.Substring(dotPos);
            }
            //逗号分隔
            int paras = (leftText.Length + 2) / 3;
            StringBuilder buffer = new StringBuilder();
            for (int i = 0; i < paras - 1; i++)
                buffer.Append("###,");
            buffer.Append("##0");
            leftText = decimal.Parse(leftText).ToString(buffer.ToString());
            return leftText + reghtText;
        }

        /// <summary>
        /// 用查询字符串的方法对指定字符串加密
        /// </summary>
        /// <param name="pwd">指定字符串</param>
        /// <returns>加密后的字符串</returns>
        public static string EncryptStr(string pwd)
        {
            return EncryptStr(pwd, pwdstrs);
        }

        /// <summary>
        /// 用查询字符串的方法对指定字符串加密
        /// </summary>
        /// <param name="pwd">指定字符串</param>
        /// <param name="sourcestr">键盘信息串</param>
        /// <returns>加密后的字符串</returns>
        public static string EncryptStr(string pwd, string sourcestr)
        {
            if (IsEmpty(pwd))
                return "";

            string strs = sourcestr;
            char[] chs = strs.ToCharArray();
            char[] pwds = pwd.ToCharArray();
            string[] posi = new string[pwds.Length];
            for (int x = 0; x < pwds.Length; x++)
            {
                int n = strs.IndexOf(pwds[x]);
                if (n < 0)
                    return "";

                if (n < 10)
                    posi[x] = "0" + n;
                else
                    posi[x] = "" + n;

            }

            pwd = "";
            for (int x = 0; x < posi.Length; x++)
                pwd = pwd + posi[x];

            return pwd;
        }

        /// <summary>
        /// 对此类中加密的字符串解密
        /// </summary>
        /// <param name="pwd">欲解密的字符串</param>
        /// <returns>解密后的字符串</returns>
        public static string UnEncryptStr(string pwd)
        {
            return UnEncryptStr(pwd, pwdstrs);
        }

        /// <summary>
        /// 对此类中加密的字符串解密
        /// </summary>
        /// <param name="pwd">欲解密的字符串</param>
        /// <param name="sourcestr">键盘信息串</param>
        /// <returns>解密后的字符串</returns>
        public static string UnEncryptStr(string pwd, string sourcestr)
        {
            if (IsEmpty(pwd))
                return pwd;
            int len = pwd.Length;
            if ((len % 2) != 0)
                return "";
            int m = 0;
            string strs = sourcestr;
            char[] unpwd = new char[pwd.Length / 2];
            for (int x = 0; x < unpwd.Length; x++)
            {
                string tmps = pwd.Substring(x * 2, 2);
                try
                {
                    m = Int32.Parse(tmps);
                }
                catch (System.Exception)
                {
                    return "";
                }
                unpwd[x] = strs[m];
            }

            pwd = "";
            for (int x = 0; x < unpwd.Length; x++)
                pwd = pwd + unpwd[x];
            return pwd;
        }
    }
}