如果你真的想运行自己的CSV解析器，你需要教你的正则表达式一些规则：
1.一个字段可以不加引号，只要它不包含引号，逗号或换行符。
1.带引号的字段可以包含任何字符;引号通过加倍进行转义。
1.逗号用作分隔符。
因此，要匹配一个CSV字段，您可以使用以下正则表达式：

(?mx)       # Verbose, multiline mode
(?<=^|,)    # Assert there is a comma or start of line before the current position.
(?:         # Start non-capturing group:
 "          # Either match an opening quote, followed by
 (?:        # a non-capturing group:
  ""        #  Either an escaped quote
 |          #  or
  [^"]+     #  any characters except quotes
 )*         # End of inner non-capturing group, repeat as needed.
 "          # Match a closing quote.
|           # OR
 [^,"\r\n]+ # Match any number of characters except commas, quotes or newlines
)           # End of outer non-capturing group
(?=,|$)     # Assert there is a comma or end-of-line after the current position

看live on regex101.com。

请不要使用正则表达式，CSV应该由解析器处理。
下面是一个现成的解析器：http://www.codeproject.com/Articles/9258/A-Fast-CSV-Reader
您也可以使用OLEDB内置解析器：http://www.switchonthecode.com/tutorials/csharp-tutorial-using-the-built-in-oledb-csv-parser
希望这有帮助

首先，这只会抓住一个群体。其次，你必须不贪婪：

(?:"(.*?)")

这并不能解决单行中多个匹配项的问题。下面是两个例子：

import re
string = '"Smith, John",25,"21/45, North Avenue",IBM'
pattern = r'(?:"(.*?)")'
re.findall(pattern, string)
> ['Smith, John', '21/45, North Avenue']

在C#中：

string pattern = @"(?:\""(.*?)\"")";
string input = @"\""Smith, John\"",25,\""21/45, North Avenue\"",IBM'";
foreach (Match m in Regex.Matches(input, pattern)) 
    Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);