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c#.net-3.5filestreamstreamreader

Will closing a FileStream close the StreamReader?


If I use a FileStream to create a StreamReader, will the StreamReader close when I close the FileStream or will I need to close the StreamReader too?

public void ReadFile()
{
    var file = new FileStream("c:\file.txt", FileMode.Open, FileAccess.Read);
    var reader = new StreamReader(file);

    try
    {
        txtFile.Text = reader.ReadToEnd();
    }
    catch (Exception)
    {
        throw;
    }
    finally
    {
        file.Close();
    }
}

Solution

  • Essentially yes. You don't actually have to close a StreamReader. If you do, all it does is closes the underlying stream.

    @Bruno makes a good point about closing the outer-most wrapper. It is good practice to close the outer-most stream and let it close underlying streams in order to ensure all resources are released properly.

    From Reflector...

    public class StreamReader : TextReader
    {
        public override void Close()
        {
            this.Dispose(true);
        }
    
        protected override void Dispose(bool disposing)
        {
            try
            {
                if ((this.Closable && disposing) && (this.stream != null))
                {
                    this.stream.Close();
                }
            }
            finally
            {
                if (this.Closable && (this.stream != null))
                {
                    this.stream = null;
                    this.encoding = null;
                    this.decoder = null;
                    this.byteBuffer = null;
                    this.charBuffer = null;
                    this.charPos = 0;
                    this.charLen = 0;
                    base.Dispose(disposing);
                }
            }
        }
    }