Can you get file path from StreamReader object?

Question

Is it possible to get the path that was used in the StreamReader constructor from the StreamReader object?

        using (StreamReader fileStream = new StreamReader(filePath))
        {
            string path = fileStream.???
        }

Answer 1

StreamReader exposes the stream from which it's reading via the BaseStream property. If the reader's stream is a FileStream, you can use its Name property to get the path of the file.

using (StreamReader reader = new StreamReader(filePath))
{
    string path = (reader.BaseStream as FileStream)?.Name;
}

Note: I renamed the variable to prevent possible confusion, since it IS a reader that HAS a stream.

In this contrived example, it's obvious that it's a FileStream but the type test is necessary if you have a method that's taking a StreamReader.

That said, you're causing the abstraction to leak by doing this. If you need to know the file name, you should explicitly require the file name or a FileStream instance.