DotNet的字符转义操作

标签：.net   c#   字符转义   

  在项目中使用到字符的转义，现在提供一种字符转义和反转义的操作方法：

1.转义符操作：

        /// <summary>
        /// 转义符操作
        /// </summary>
        /// <param name="s"></param>
        /// <param name="charToEliminate"></param>
        /// <returns></returns>
        public static string EscapeChar(string s, char charToEliminate)
        {
            char escapeChar;
            char substituteChar;

            GetEscapeAndEncodingChars(charToEliminate, out escapeChar, out substituteChar);

            int i;
            for (i = 0; i < s.Length; i++)
            {
                if (s[i] == charToEliminate || s[i] == escapeChar)
                {
                    break;
                }
            }

            if (i == s.Length)
            {
                return s;
            }

            var sb = new StringBuilder(s.Substring(0, i), s.Length + 16);

            for (; i < s.Length; i++)
            {
                var c = s[i];

                if (c == charToEliminate)
                {
                    sb.Append(escapeChar);
                    sb.Append(substituteChar);
                }
                else if (c == escapeChar)
                {
                    sb.Append(escapeChar, 2);
                }
                else
                {
                    sb.Append(c);
                }
            }

            return sb.ToString();
        }

2.反转义符操作：

        /// <summary>
        /// 反转义符操作
        /// </summary>
        /// <param name="s"></param>
        /// <param name="eliminatedChar"></param>
        /// <returns></returns>
        public static string UnescapeChar(string s, char eliminatedChar)
        {
            ArgumentValidator.ThrowIfNull(s, "s");

            char escapeChar;
            char substituteChar;

            GetEscapeAndEncodingChars(eliminatedChar, out escapeChar, out substituteChar);

            if (-1 == s.IndexOf(escapeChar))
            {
                return s;
            }

            var sb = new StringBuilder(s.Length);

            for (var i = 0; i < s.Length; i++)
            {
                var c = s[i];

                var next = i + 1;

                if (c != escapeChar || next == s.Length)
                {
                    sb.Append(c);
                    continue;
                }

                if (s[next] == escapeChar)
                {
                    sb.Append(escapeChar);
                    i++;
                }
                else if (s[next] == substituteChar)
                {
                    sb.Append(eliminatedChar);
                    i++;
                }
                else
                {
                    var msg = ("Invalid escaped string ‘{0}‘. Position {1} has escape character, but it is not followed by "
                        + "another escape character or by the substitute character").Fi(s, i);
                    throw new AssertionViolationException(msg);
                }
            }

            return sb.ToString();
        }

3.获取转义符和编码字符：

        /// <summary>
        /// 获取转义符和编码字符
        /// </summary>
        /// <param name="charToEliminate"></param>
        /// <param name="escapeChar"></param>
        /// <param name="encodingChar"></param>
        private static void GetEscapeAndEncodingChars(char charToEliminate, out char escapeChar, out char encodingChar)
        {
            var i = MEscapeChars[0] == charToEliminate ? 1 : 0;
            escapeChar = MEscapeChars[i];
            i++;

            if (MEscapeChars[i] == charToEliminate)
            {
                i++;
            }
            encodingChar = MEscapeChars[i];
        }

本文出自 “彭泽0902” 博客，请务必保留此出处http://pengze0902.blog.51cto.com/7693836/1862764

DotNet的字符转义操作

标签：.net   c#   字符转义   

原文地址：http://pengze0902.blog.51cto.com/7693836/1862764