StringHelper-字符串辅助类

using System;
using System.Collections.Generic;

using System.Text;
using System.Globalization;
using System.Text.RegularExpressions;

namespace Framework
{
    /// <summary>
    /// 字符串辅助类
    /// </summary>
    public static class StringHelper
    {
        /// <summary>
        /// 截取字符串的后部分
        /// </summary>
        /// <param name="source">原字符串</param>
        /// <param name="value">拆分字符串</param>
        /// <returns>截取后的字符串</returns>
        public static string SubstringAfter(this string source, string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return source;
            }
            CompareInfo compareInfo = CultureInfo.InvariantCulture.CompareInfo;
            int index = compareInfo.IndexOf(source, value, CompareOptions.Ordinal);
            if (index < 0)
            {
                return string.Empty;
            }
            return source.Substring(index + value.Length);
        }
        /// <summary>
        /// 截取字符串的前部分
        /// </summary>
        /// <param name="source">原字符串</param>
        /// <param name="value">拆分字符串</param>
        /// <returns>截取后的字符串</returns>
        public static string SubstringBefore(this string source, string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return value;
            }

            CompareInfo compareInfo = CultureInfo.InvariantCulture.CompareInfo;
            int index = compareInfo.IndexOf(source, value, CompareOptions.Ordinal);
            if (index < 0)
            {
                return string.Empty;
            }

            return source.Substring(0, index);
        }


        /// <summary>
        /// 追加字符串，用分隔符分隔，默认分隔符为“,”
        /// </summary>
        /// <param name="sb">StringBulider对象</param>
        /// <param name="append">要追加的字符串</param>
        /// <param name="split">分隔符</param>
        public static void AppendString(this StringBuilder sb, string append, string split = ",")
        {
            if (sb.Length == 0)
            {
                sb.Append(append);
                return;
            } 
            sb.Append(split);
            sb.Append(append);
        }
        /// <summary>
        /// 替换所有HTML标签为空
        /// </summary>
        /// <param name="input">The string whose values should be replaced.</param>
        /// <returns>A string.</returns>
        public static string RemoveHtml(this string input)
        {
            var stripTags = new Regex("</?[a-z][^<>]*>", RegexOptions.IgnoreCase);
            return stripTags.Replace(input, string.Empty);
        }
    }
}