Does .Disposing a StreamWriter close the underlying stream?

Question

The StreamWriter.Close() says it also closes the underlying stream of the StreamWriter. What about StreamWriter.Dispose ? Does Dispose also dispose and/or close the underlyi

Answer 1

The answer is simple, and provided above: yes, disposing a stream closes any underlying stream. Here is an example:

    public static string PrettyPrintXML_bug(XDocument document)
    {
        string Result = "";
        using (MemoryStream mStream = new MemoryStream())
        {
            using (XmlTextWriter writer = new XmlTextWriter(mStream, Encoding.Unicode))
            {
                writer.Formatting = Formatting.Indented; // <<--- this does the trick
                // Write the XML into a formatting XmlTextWriter
                document.WriteTo(writer);
                // change the memory stream from write to read
                writer.Flush();
                mStream.Flush();
            } // <-- <-- <-- <-- <-- <-- <-- <-- <-- <-- this also "closes" mStream
            mStream.Position = 0;//rewind    <-- <-- <-- "cannot Read/Write/Seek"
            // Read MemoryStream contents into a StreamReader.
            using (StreamReader sReader = new StreamReader(mStream)) //  <-- <-- Exception: Cannot access a closed stream
            {
                // Extract the text from the StreamReader.
                Result = sReader.ReadToEnd();
            }
        }
        return Result;
    }

and here the solution, where you have to delay Dispose to where the underlying MemoryStream is not needed anymore:

    public static string PrettyPrintXML(XDocument document)
    {
        string Result = "";
        using (MemoryStream mStream = new MemoryStream())
        {
            using (XmlTextWriter writer = new XmlTextWriter(mStream, Encoding.Unicode))
            {
                writer.Formatting = Formatting.Indented; // <<--- this does the trick
                // Write the XML into a formatting XmlTextWriter
                document.WriteTo(writer);
                // change the memory stream from write to read
                writer.Flush();
                writer.Close();
                mStream.Flush();
                mStream.Position = 0;//rewind
                // Read MemoryStream contents into a StreamReader.
                using (StreamReader sReader = new StreamReader(mStream))
                {
                    // Extract the text from the StreamReader.
                    Result = sReader.ReadToEnd();
                }
            }// <-- here the writer may be Disposed
        }
        return Result;
    }

Looking at these examples, I do not understand why closing the underlying stream is a feature.

I just liked to share this.