仅当逗号在双引号C#之外时才用逗号分割字符串

You can try with Lookaround

They do not consume characters in the string, but only assert whether a match is possible or not.

(?<="),(?=")

Here is online demo and tested at regexstorm

Pattern explanation is very simple

  (?<=                     look behind to see if there is:
    "                        '"'
  )                        end of look-behind
  ,                        ','
  (?=                      look ahead to see if there is:
    "                        '"'
  )                        end of look-ahead

This is just basic CSV parsing, and there are libraries out there to do it already. I would recommend taking a look at CsvHelper which I've used before rather than trying to re-invent the wheel.

You can include this in your project really easily by using the Package Manager Console and typing:

Install-Package CsvHelper

Instead of rolling out your own CSV parser, use existing libraries. There is TextFieldParser class which is available with Visual Basic, Just add reference to Microsoft.VisualBasic under project references then you can do:

TextFieldParser textFieldParser = new TextFieldParser(@"E:\Project.csv");
textFieldParser.TextFieldType = FieldType.Delimited;
textFieldParser.SetDelimiters(",");
while (!textFieldParser.EndOfData)
{
    string[] values = textFieldParser.ReadFields();
    Console.WriteLine(string.Join("---", values));//printing the row
}
textFieldParser.Close();

Hey you can also use this regex

var result = Regex.Split(samplestring, ",(?=(?:[^']*'[^']*')*[^']*$)");