How to write a value which contain comma to a CSV file in c#?

Simply put your data inside the backslash like this: “\”” + yourdata + “\””. Take a look on the example below:

StringWriter csv = new StringWriter();
// Generate header of the CSV file
csv.WriteLine(string.Format("{0},{1}", "Header 1", "Header 2"));
// Generate content of the CSV file
foreach (var item in YourListData)
{
    csv.WriteLine(string.Format("{0},{1}", item.Data1, "\"" + item.Data2 + "\""));
}

return File(new System.Text.UTF8Encoding().GetBytes(csv.ToString()), "application/csv", string.Format("{0}{1}", "YourFileName", ".csv"));

In the example: Your data2 may contains comma “,”