在c#中,我可以将字符串值转换为字符串文字,我将在代码中看到它的方式吗?我想用转义序列替换制表符,换行符等。

如果这段代码:

Console.WriteLine(someString);

生产:

Hello
World!

我想要这样的代码:

Console.WriteLine(ToLiteral(someString));

生产:

\tHello\r\n\tWorld!\r\n

当前回答

Hallgrim的回答非常棒。这里有一个小调整,以防您需要用c#正则表达式解析额外的空白字符和换行符。我需要在序列化的JSON值插入到谷歌表的情况下,遇到了麻烦,因为代码正在插入制表符,+,空格等。

  provider.GenerateCodeFromExpression(new CodePrimitiveExpression(input), writer, null);
  var literal = writer.ToString();
  var r2 = new Regex(@"\"" \+.\n[\s]+\""", RegexOptions.ECMAScript);
  literal = r2.Replace(literal, "");
  return literal;

其他回答

很久以前,我发现了这个:

private static string ToLiteral(string input)
{
    using (var writer = new StringWriter())
    {
        using (var provider = CodeDomProvider.CreateProvider("CSharp"))
        {
            provider.GenerateCodeFromExpression(new CodePrimitiveExpression(input), writer, null);
            return writer.ToString();
        }
    }
}

这段代码:

var input = "\tHello\r\n\tWorld!";
Console.WriteLine(input);
Console.WriteLine(ToLiteral(input));

生产:

    Hello
    World!
"\tHello\r\n\tWorld!"

最近,Graham发现你可以在NuGet上使用Roslyn的Microsoft.CodeAnalysis.CSharp包:

private static string ToLiteral(string valueTextForCompiler)
{
    return Microsoft.CodeAnalysis.CSharp.SymbolDisplay.FormatLiteral(valueTextForCompiler, false);
}

Try:

var t = HttpUtility.JavaScriptStringEncode(s);

Hallgrim的回答非常棒。这里有一个小调整,以防您需要用c#正则表达式解析额外的空白字符和换行符。我需要在序列化的JSON值插入到谷歌表的情况下,遇到了麻烦,因为代码正在插入制表符,+,空格等。

  provider.GenerateCodeFromExpression(new CodePrimitiveExpression(input), writer, null);
  var literal = writer.ToString();
  var r2 = new Regex(@"\"" \+.\n[\s]+\""", RegexOptions.ECMAScript);
  literal = r2.Replace(literal, "");
  return literal;
public static class StringEscape
{
  static char[] toEscape = "\0\x1\x2\x3\x4\x5\x6\a\b\t\n\v\f\r\xe\xf\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\"\\".ToCharArray();
  static string[] literals = @"\0,\x0001,\x0002,\x0003,\x0004,\x0005,\x0006,\a,\b,\t,\n,\v,\f,\r,\x000e,\x000f,\x0010,\x0011,\x0012,\x0013,\x0014,\x0015,\x0016,\x0017,\x0018,\x0019,\x001a,\x001b,\x001c,\x001d,\x001e,\x001f".Split(new char[] { ',' });

  public static string Escape(this string input)
  {
    int i = input.IndexOfAny(toEscape);
    if (i < 0) return input;

    var sb = new System.Text.StringBuilder(input.Length + 5);
    int j = 0;
    do
    {
      sb.Append(input, j, i - j);
      var c = input[i];
      if (c < 0x20) sb.Append(literals[c]); else sb.Append(@"\").Append(c);
    } while ((i = input.IndexOfAny(toEscape, j = ++i)) > 0);

    return sb.Append(input, j, input.Length - j).ToString();
  }
}

我提交了自己的实现,它处理空值,并且由于使用数组查找表、手动十六进制转换和避免开关语句,因此性能应该更好。

using System;
using System.Text;
using System.Linq;

public static class StringLiteralEncoding {
  private static readonly char[] HEX_DIGIT_LOWER = "0123456789abcdef".ToCharArray();
  private static readonly char[] LITERALENCODE_ESCAPE_CHARS;

  static StringLiteralEncoding() {
    // Per http://msdn.microsoft.com/en-us/library/h21280bw.aspx
    var escapes = new string[] { "\aa", "\bb", "\ff", "\nn", "\rr", "\tt", "\vv", "\"\"", "\\\\", "??", "\00" };
    LITERALENCODE_ESCAPE_CHARS = new char[escapes.Max(e => e[0]) + 1];
    foreach(var escape in escapes)
      LITERALENCODE_ESCAPE_CHARS[escape[0]] = escape[1];
  }

  /// <summary>
  /// Convert the string to the equivalent C# string literal, enclosing the string in double quotes and inserting
  /// escape sequences as necessary.
  /// </summary>
  /// <param name="s">The string to be converted to a C# string literal.</param>
  /// <returns><paramref name="s"/> represented as a C# string literal.</returns>
  public static string Encode(string s) {
    if(null == s) return "null";

    var sb = new StringBuilder(s.Length + 2).Append('"');
    for(var rp = 0; rp < s.Length; rp++) {
      var c = s[rp];
      if(c < LITERALENCODE_ESCAPE_CHARS.Length && '\0' != LITERALENCODE_ESCAPE_CHARS[c])
        sb.Append('\\').Append(LITERALENCODE_ESCAPE_CHARS[c]);
      else if('~' >= c && c >= ' ')
        sb.Append(c);
      else
        sb.Append(@"\x")
          .Append(HEX_DIGIT_LOWER[c >> 12 & 0x0F])
          .Append(HEX_DIGIT_LOWER[c >>  8 & 0x0F])
          .Append(HEX_DIGIT_LOWER[c >>  4 & 0x0F])
          .Append(HEX_DIGIT_LOWER[c       & 0x0F]);
    }

    return sb.Append('"').ToString();
  }
}