Stream Reader

Frank Kerrigan

This does not appear to be working and I can't figure out why MemoryStream ms = new MemoryStream(); string message; ….some code here to fill the memory stream…. Using (StreamReader sr = new StreamReader(ms)) { message = sr.ReadToEnd(); } ms.Position = 0;

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Colin Angus Mackay

Frank Kerrigan wrote:

This does not appear to be working and I can't figure out why

What exactly do you mean by "not working"?

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Frank Kerrigan

This code was taken from a live web service that had been running perfectly happily for nearly 3 months and then all of a sudden stopped working, throwing the ObjectDisposedException.

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Alois Kraus

This is a lifetime issue because the underlying stream has been finalized before the StreamReader was flushed. This article should help you to get more light into this issue: http://geekswithblogs.net/akraus1/articles/81629.aspx Yours, Alois Kraus

Colin Angus Mackay

The reason is because the using block closes the StreamReader when you move out of the scope of the using block. When you close a StreamReader OR a StreamWriter, however, the underlying stream object is also closed and thus disposed. If your stream was a FileStream then that might make logical sense but it is not so obvious with a MemoryStream because you probably want to use it as temporary storage or pass to another method for further processing etc. Even if you did not use the using block the MemoryStream would still be closed the moment the StreamReader is disposed of or garbage collected. I've no idea why it would just suddenly show up now after so many months - That is a curiosity.

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Frank Kerrigan

Thanks guys

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Colin Angus Mackay

Alois Kraus wrote:

http://geekswithblogs.net/akraus1/articles/81629.aspx

Sorry, that link doesn't work for me.

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Judah Gabriel Himango

sr.ReadToEnd will read to the end from the current position. Make sure the position is 0 before reading to end. Also, don't touch the memory stream after it has been disposed. The using(...) block will dispose the object; it will actually compile down to this:

StreamReader sr = null;
try
{
sr = new StreamReader(ms);
message = sr.ReadToEnd();
}
finally
{
if(sr != null)
{
sr.Dispose();
}
}

Since it gets disposed when the using block leaves scope, callign ms.Position = 0 after the using scope is going to cause problems.

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