How to Get a File's Encoding with C#

Introduction

This tip describes how to get a file's encoding with C#.

Background

For some reason, it took me a while to figure it out. All the forums and discussions I found did not have the exact correct way (meaning when I tried to use them, I got wrong results). Although some came very close...

Using the Code

Simply copy paste.

/// <summary
/// Get File's Encoding
/// </summary>
/// <param name="filename">The path to the file
private static Encoding GetEncoding(string filename)
{
    // This is a direct quote from MSDN:  
    // The CurrentEncoding value can be different after the first
    // call to any Read method of StreamReader, since encoding
    // autodetection is not done until the first call to a Read method.

    using (var reader = new StreamReader(filename, Encoding.Default, true))
    {
        if (reader.Peek() >= 0) // you need this!
            reader.Read();

        return reader.CurrentEncoding;
    }
}

Points of Interest

The key to making it work was hidden in the remarks section in MSDN: only after performing a read, we will have the correct CurrentEncoding value.

I hope this helps!