Forcing StreamWriter to change Encoding

问题:

I am trying to save a file using DialogResult and StringBuilder. After making the text, I am calling the following code to save the file:

    if (dr == DialogResult.OK)
    {

        StreamWriter sw = new StreamWriter(saveFileDialog1.FileName);

        sw.Write(sb.ToString());
        sw.Close();
    }

I tried to add the second parameter to StreamWriter as Encoding.UTF8 but since the first argument is a string rather than a Stream, it does not compile it.

How can I convert that string to a stream to be able to pass the second parameter as Encoding?

The reason for this, is that somewhere in my text I have µ but when the file is saved it shows like μ so the µ is getting screwd!

Thanks

回答1:

Just wrap it in a FileStream.

StreamWriter sw = new StreamWriter(
    new FileStream(saveFileDialog1.FileName, FileMode.Open, FileAccess.ReadWrite),
    Encoding.UTF8
);

If you want to append, use FileMode.Append instead.

You should also call Dispose() on a try/finally block, or use a using block to dispose the object when it exceeds the using scope:

using(
    var sw = new StreamWriter(
        new FileStream(saveFileDialog1.FileName, FileMode.Open, FileAccess.ReadWrite),
        Encoding.UTF8
    )
)
{
    sw.Write(sb.ToString());
}

This will properly close and dispose the streams across all exception paths.

回答2:

There is a constructor for filename, appendMode, encoding.

With a proper using block it looks like:

if (dr == DialogResult.OK)
{
    using (StreamWriter sw = new StreamWriter(saveFileDialog1.FileName, 
           false, Encoding.UTF8))
    {
      sw.Write(sb.ToString());
      //sw.Close();
    }
}

回答3:

There is a StreamWriter(string path, bool append, Encoding encoding) constructor - you could just explicitly specify the append flag too?

I said you ought to wrap your StreamWriter in a using too, i.e.

if (dr == DialogResult.OK)
{
    using(StreamWriter sw = new StreamWriter(saveFileDialog1.FileName, false, Encoding.UTF8)) {
        sw.Write(sb.ToString());
        sw.Close();
    }
}

although realistically this won't make any difference here. This effectively puts a try/finally around the code so that the StreamWriter will get cleaned up (it'll call sw.Dispose() even if an exception gets thrown in the meantime. (Some people will say this also means you no longer need the .Close since the Dispose will take care of that too but I prefer to have it anyway.)

回答4:

setting UTF8 encoding working with Arabic font is the best thing I did:

 using (var sw = new StreamWriter(

 new FileStream(temporaryFilePath,    
               FileMode.Create,
               FileAccess.ReadWrite), 
               Encoding.UTF8))
            {
                sw.Write(sb.ToString());
            }
 )