c#, Excel + csv: how to get the correct encoding?

This worked perfect for me:

private const int WIN_1252_CP = 1252; // Windows ANSI codepage 1252

    this._writer = new StreamWriter(fileName, false, Encoding.GetEncoding(WIN_1252_CP));

CSV encoding issues (Microsoft Excel)

try the following:

using (var sw = File.Create(Path.Combine(txtPath.Text, "UTF8.csv")))
{
  var preamble = Encoding.UTF8.GetPreamble();
  sw.Write(preamble, 0, preamble.Length);
  var data = Encoding.UTF8.GetBytes("懘荧,\"Hello\",text");
  sw.Write(data, 0, data.Length);
}

It writes the proper UTF8 preamble to the file before writing the UTF8 encoded CSV.

This solution is written up as a fix for a Java application however you should be able to do something similar in C#. You may also want to look at the documentation on the StreamWriter class, in the remarks it refers to the Byte Order Mark (BOM).