c# - Converting Unicode to Windows-1252 for vCards

Question

I am trying to write a program in C# that will split a vCard (VCF) file with multiple contacts into individual files for each contact. I understand that the vCard needs to be saved as ANSI (1252) for most mobile phones to read them.

However, if I open a VCF file using StreamReader and then write it back with StreamWriter (setting 1252 as the Encoding format), all special characters like ?, ? and ? are getting written as ?. Surely ANSI (1252) would support these characters. How do I fix this?

Edit: Here's the piece of code I use to read and write the file.

private void ReadFile()
{
   StreamReader sreader = new StreamReader(sourceVCFFile);
   string fullFileContents = sreader.ReadToEnd();
}

private void WriteFile()
{
   StreamWriter swriter = new StreamWriter(sourceVCFFile, false, Encoding.GetEncoding(1252));
   swriter.Write(fullFileContents);
}

Answer 1

You are correct in assuming that Windows-1252 supports the special characters you listed above (for a full list see the Wikipedia entry).

using (var writer = new StreamWriter(destination, true, Encoding.GetEncoding(1252)))
{
    writer.WriteLine(source);
}

In my test app using the code above it produced this result:

Look at the cool letters I can make: ?, ?, and ?!

No question marks to be found. Are you setting the encoding when your reading it in with StreamReader?

EDIT: You should just be able to use Encoding.Convert to convert the UTF-8 VCF file into Windows-1252. No need for Regex.Replace. Here is how I would do it:

// You might want to think of a better method name.
public string ConvertUTF8ToWin1252(string source)
{
    Encoding utf8 = new UTF8Encoding();
    Encoding win1252 = Encoding.GetEncoding(1252);

    byte[] input = source.ToUTF8ByteArray();  // Note the use of my extension method
    byte[] output = Encoding.Convert(utf8, win1252, input);

    return win1252.GetString(output);
}

And here is how my extension method looks:

public static class StringHelper
{
    // It should be noted that this method is expecting UTF-8 input only,
    // so you probably should give it a more fitting name.
    public static byte[] ToUTF8ByteArray(this string str)
    {
        Encoding encoding = new UTF8Encoding();
        return encoding.GetBytes(str);
    }
}

---

Also you'll probably want to add usings to your ReadFile and WriteFile methods.