Im trying to prompt a downloadable text file (.txt), but I get this error:
Cannot access a closed Stream.
I have looked at simular questions in here: Cannot Access Closed Stream But it was not very useful.
Here is my code:
private FileStreamResult Export()
{
string name = "filename.txt";
MemoryStream stream = new MemoryStream();
using (StreamWriter writer = new StreamWriter(stream))
{
StringBuilder sb = new StringBuilder();
sb.Append("A text...");
writer.WriteLine(sb.ToString());
}
return File(stream, "text/plain", name);
}
UPDATE (working copy):
This gives me an blank text file.
private FileResult Export()
{
string name = "filename.txt";
MemoryStream stream = new MemoryStream();
StreamWriter writer = new StreamWriter(stream);
StringBuilder sb = new StringBuilder();
sb.Append("A text...");
writer.WriteLine(sb.ToString());
writer.Flush();
stream.Seek(0, SeekOrigin.Begin);
return File(stream, "text/plain", name);
}
That is correct, when you wrap a stream in another stream, calling .Close()
or .Dispose()
on any of them will dispose the whole stream. In this case, wrapping the MemoryStream
in a StreamWriter
means that when the using
statement completes the StreamWriter
and MemoryStream
are both disposed.
My guess is since you are returning a FileStreamResult
the encapsulating File
will close the stream for you after the stream is no longer used. In this case, you do not want to use the using
statement and will want to leave the stream open when returning it.
UPDATE
Since a stream is forward access you'll need to see the stream back to the beginning to allow the data to be read back out.
stream.Seek(0, SeekOrigin.Begin);
Just remove that using
statement - you are passing disposed object reference to File
method and you that's the reason why you get exception. From MSDN,
The StreamWriter object calls Dispose on the provided Stream object when StreamWriter.Dispose is called.
I believe File
will dispose stream by itself after usage (not verified by looking at source code).
UPDATE:
writer.Flush();
before return statement should help you
You have to set the position of the memorystream to 0 before using it in your FileStreamResult, otherwise it will be read from current position (IE the end of the stream).
stream.Position = 0;
return File(stream, "text/plain", name);
Just had the same thing.
I know this thread is ancient, just hoping to aid others having the same issue.
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