Asp.net core IActionResult csv 编码问题

Question

I have a problem when trying to save a csv file though an IActionResult. Special characters like åøæ will not be shown properly when opening the csv file. I have tried a lot of different approaches, but nothing seems to work. My latest attempt was trying to use the CsvHelper library but doesn't seem to work neither. Here is my latest attempt.

        byte[] result;
        await using (var memoryStream = new MemoryStream())
        await using (var streamWriter = new StreamWriter(memoryStream, new UTF8Encoding(true)))
        {
            var csvWriter = new CsvWriter(streamWriter, CultureInfo.InvariantCulture);
            csvWriter.Configuration.Delimiter = ";";
            await csvWriter.WriteRecordsAsync(data);
            await streamWriter.FlushAsync();
            result = memoryStream.ToArray();
        }

        return new FileStreamResult(new MemoryStream(result), "text/csv")
        { FileDownloadName = $"data.csv" };

I hobe someone can help me, thanks in advance.

Answer 1

As far as I know, this issue is related with Excel not asp.net core application. We could set the download file format to use utf-8 , but excel doesn't open it with right format.

You could open your csv file and find it shows as below:

But excel shows like this:

To force excel to show the special character, you should follow below steps:

1.Open Excel and new a empty excel

2.Import the data using Data-->Import External Data --> Import Data

3.Select the file type of "csv" and browse to your file

4.In the import wizard change the File_Origin to "65001 UTF" (or choose correct language character identifier)

5.Change the Delimiter to comma

6.Select where to import to and Finish

Generate csv codes:

          List<Student> students = new List<Student>
{
    new Student { Id = 1, FirstName = "éåæÉà;some other value", LastName = "Kanjilal" },
    new Student { Id = 2, FirstName = "Steve", LastName = "Smith" },
    new Student { Id = 3, FirstName = "Anand", LastName = "Narayaswamy"}
};
            try
            {
                StringBuilder stringBuilder = new StringBuilder();
                stringBuilder.AppendLine("Id,FirstName,LastName");
                foreach (var student in students)
                {
                    stringBuilder.AppendLine($"{student.Id},  { student.FirstName},{ student.LastName}");
                }
                return File(Encoding.UTF8.GetBytes
                (stringBuilder.ToString()), "text/csv;charset=utf-8", "student.csv");
            }
            catch
            {
                return Error();
            }