我可以将 C# 字符串值转换为转义的字符串文字吗
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Can I convert a C# string value to an escaped string literal
提问by Hallgrim
In C#, can I convert a string value to a string literal, the way I would see it in code? I would like to replace tabs, newlines, etc. with their escape sequences.
在 C# 中，我可以将字符串值转换为字符串文字，就像我在代码中看到的那样吗？我想用它们的转义序列替换制表符、换行符等。
If this code:
如果这段代码：
Console.WriteLine(someString);
produces:
产生：
Hello
World!
I want this code:
我想要这个代码：
Console.WriteLine(ToLiteral(someString));
to produce:
生产：
\tHello\r\n\tWorld!\r\n
采纳答案by Hallgrim
I found this:
我找到了这个：
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();
}
}
}
This code:
这段代码：
var input = "\tHello\r\n\tWorld!";
Console.WriteLine(input);
Console.WriteLine(ToLiteral(input));
Produces:
产生：
Hello
World!
"\tHello\r\n\tWorld!"
回答by Nelson Reis
Interesting question.
有趣的问题。
If you can't find a better method, you can always replace.
In case you're opting for it, you could use this C# Escape Sequence List:
如果你找不到更好的方法，你可以随时更换。
如果你选择它，你可以使用这个C# 转义序列列表：
- \' - single quote, needed for character literals
- \" - double quote, needed for string literals
- \ - backslash
- \0 - Unicode character 0
- \a - Alert (character 7)
- \b - Backspace (character 8)
- \f - Form feed (character 12)
- \n - New line (character 10)
- \r - Carriage return (character 13)
- \t - Horizontal tab (character 9)
- \v - Vertical quote (character 11)
- \uxxxx - Unicode escape sequence for character with hex value xxxx
- \xn[n][n][n] - Unicode escape sequence for character with hex value nnnn (variable length version of \uxxxx)
- \Uxxxxxxxx - Unicode escape sequence for character with hex value xxxxxxxx (for generating surrogates)
- \' - 单引号，字符文字需要
- \" - 双引号，字符串文字需要
- \ - 反斜杠
- \0 - Unicode 字符 0
- \a - 警报（字符 7）
- \b - 退格（字符 8）
- \f - 换页（字符 12）
- \n - 新行（字符 10）
- \r - 回车（字符 13）
- \t - 水平制表符（字符 9）
- \v - 垂直引号（字符 11）
- \uxxxx - 具有十六进制值 xxxx 的字符的 Unicode 转义序列
- \xn[n][n][n] - 具有十六进制值 nnnn 的字符的 Unicode 转义序列（\uxxxx 的可变长度版本）
- \Uxxxxxxxx - 具有十六进制值 xxxxxxxx 的字符的 Unicode 转义序列（用于生成代理）
This list can be found in the C# Frequently Asked Questions What character escape sequences are available?
此列表可在 C# 常见问题解答中找到 哪些字符转义序列可用？
回答by Cristian Diaconescu
EDIT: A more structured approach, including all escape sequences for strings and chars.
Doesn't replace unicode characters with their literal equivalent.
Doesn't cook eggs, either.
编辑：一种更结构化的方法，包括strings 和chars 的所有转义序列。
不将 unicode 字符替换为其文字等效项。也不会煮鸡蛋。
public class ReplaceString
{
static readonly IDictionary<string, string> m_replaceDict
= new Dictionary<string, string>();
const string ms_regexEscapes = @"[\a\b\f\n\r\t\v\""]";
public static string StringLiteral(string i_string)
{
return Regex.Replace(i_string, ms_regexEscapes, match);
}
public static string CharLiteral(char c)
{
return c == '\'' ? @"'\''" : string.Format("'{0}'", c);
}
private static string match(Match m)
{
string match = m.ToString();
if (m_replaceDict.ContainsKey(match))
{
return m_replaceDict[match];
}
throw new NotSupportedException();
}
static ReplaceString()
{
m_replaceDict.Add("\a", @"\a");
m_replaceDict.Add("\b", @"\b");
m_replaceDict.Add("\f", @"\f");
m_replaceDict.Add("\n", @"\n");
m_replaceDict.Add("\r", @"\r");
m_replaceDict.Add("\t", @"\t");
m_replaceDict.Add("\v", @"\v");
m_replaceDict.Add("\", @"\");
m_replaceDict.Add("string someString1 = "\tHello\r\n\tWorld!\r\n";
string someString2 = @"\tHello\r\n\tWorld!\r\n";
Console.WriteLine(someString1);
Console.WriteLine(someString2);
", @" Hello
World!
\tHello\r\n\tWorld!\r\n
");
//The SO parser gets fooled by the verbatim version
//of the string to replace - @"\"""
//so use the 'regular' version
m_replaceDict.Add("\"", "\\"");
}
static void Main(string[] args){
string s = "here's a \"\n\tstring\" to test";
Console.WriteLine(ReplaceString.StringLiteral(s));
Console.WriteLine(ReplaceString.CharLiteral('c'));
Console.WriteLine(ReplaceString.CharLiteral('\''));
}
}
回答by rfgamaral
Code:
代码：
public static class StringHelpers
{
private static Dictionary<string, string> escapeMapping = new Dictionary<string, string>()
{
{"\"", @"\\"""},
{"\\", @"\"},
{"\a", @"\a"},
{"\b", @"\b"},
{"\f", @"\f"},
{"\n", @"\n"},
{"\r", @"\r"},
{"\t", @"\t"},
{"\v", @"\v"},
{"var t = HttpUtility.JavaScriptStringEncode(s);
", @" static string ToLiteral(string input) {
StringBuilder literal = new StringBuilder(input.Length + 2);
literal.Append("\"");
foreach (var c in input) {
switch (c) {
case '\'': literal.Append(@"\'"); break;
case '\"': literal.Append("\\""); break;
case '\': literal.Append(@"\"); break;
case 'using System;
using System.Globalization;
using System.Text;
public static class CodeHelper
{
public static string ToLiteral(this string input)
{
var literal = new StringBuilder(input.Length + 2);
literal.Append("\"");
foreach (var c in input)
{
switch (c)
{
case '\'': literal.Append(@"\'"); break;
case '\"': literal.Append("\\""); break;
case '\': literal.Append(@"\"); break;
case 'private static string ToLiteral(string input)
{
using (var writer = new StringWriter())
{
using (var provider = CodeDomProvider.CreateProvider("CSharp"))
{
provider.GenerateCodeFromExpression(new CodePrimitiveExpression(input), writer, new CodeGeneratorOptions {IndentString = "\t"});
var literal = writer.ToString();
literal = literal.Replace(string.Format("\" +{0}\t\"", Environment.NewLine), "");
return literal;
}
}
}
': literal.Append(@"##代码##"); break;
case '\a': literal.Append(@"\a"); break;
case '\b': literal.Append(@"\b"); break;
case '\f': literal.Append(@"\f"); break;
case '\n': literal.Append(@"\n"); break;
case '\r': literal.Append(@"\r"); break;
case '\t': literal.Append(@"\t"); break;
case '\v': literal.Append(@"\v"); break;
default:
if (Char.GetUnicodeCategory(c) != UnicodeCategory.Control)
{
literal.Append(c);
}
else
{
literal.Append(@"\u");
literal.Append(((ushort)c).ToString("x4"));
}
break;
}
}
literal.Append("\"");
return literal.ToString();
}
}
': literal.Append(@"##代码##"); break;
case '\a': literal.Append(@"\a"); break;
case '\b': literal.Append(@"\b"); break;
case '\f': literal.Append(@"\f"); break;
case '\n': literal.Append(@"\n"); break;
case '\r': literal.Append(@"\r"); break;
case '\t': literal.Append(@"\t"); break;
case '\v': literal.Append(@"\v"); break;
default:
// ASCII printable character
if (c >= 0x20 && c <= 0x7e) {
literal.Append(c);
// As UTF16 escaped character
} else {
literal.Append(@"\u");
literal.Append(((int)c).ToString("x4"));
}
break;
}
}
literal.Append("\"");
return literal.ToString();
}
"},
};
private static Regex escapeRegex = new Regex(string.Join("|", escapeMapping.Keys.ToArray()));
public static string Escape(this string s)
{
return escapeRegex.Replace(s, EscapeMatchEval);
}
private static string EscapeMatchEval(Match m)
{
if (escapeMapping.ContainsKey(m.Value))
{
return escapeMapping[m.Value];
}
return escapeMapping[Regex.Escape(m.Value)];
}
}
Output:
输出：
##代码##Is this what you want?
这是你想要的吗？
回答by ICR
回答by Arsen Zahray
try:
尝试：
##代码##回答by Smilediver
Fully working implementation, including escaping of Unicode and ASCII non printable characters. Does not insert "+" signs like Hallgrim's answer.
完整的工作实现，包括转义 Unicode 和 ASCII 不可打印字符。不会像Hallgrim's answer那样插入“+”号。
##代码##回答by Shqdooow
What about Regex.Escape(String)?
Regex.Escape escapes a minimal set of characters (\, *, +, ?, |, {, [, (,), ^, $,., #, and white space) by replacing them with their escape codes.
Regex.Escape 通过用转义码替换它们来转义最少的一组字符（\、*、+、?、|、{、[、(、)、^、$、.、# 和空格）。
回答by deerchao
Here is a little improvement for Smilediver's answer, it will not escape all no-ASCII chars but only these are really needed.
这是 Smilediver 的答案的一些改进，它不会转义所有非 ASCII 字符，但只有这些才是真正需要的。
##代码##回答by lesur
Hallgrim's answer is excellent, but the "+", newline and indent additions were breaking functionality for me. An easy way around it is:
Hallgrim 的回答非常好，但是“+”、换行符和缩进添加对我来说破坏了功能。一个简单的方法是：
##代码##