What happens if StreamReader or StreamWriter are not closed?

问题

I'm working on an assignment for a professor that is strict about LOC. For this reason I'd like to do the following:

(new StreamWriter(saveFileDialog.FileName)).Write(textBox.Text);

instead of

StreamWriter sw = new StreamWriter(saveFileDialog.FileName);
sw.Write(textBox.Text);
sw.Close();

In the first example I don't close the stream. Is this ok? Will it cause any security or memory problems?

回答1:

You may not get any output, or incomplete output. Closing the writer also flushes it. Rather than manually calling Close at all, I'd use a using statement... but if you're just trying to write text to a file, use a one-shot File.WriteAllText call:

File.WriteAllText(saveFileDialog.FileName, textBox.Text);

回答2:

Maybe your tutor is looking for:

File.WriteAllText(saveFileDialog.FileName, textbox.Text);

It's reasonable to prefer concise code, but not at the expense of readability or correctness.

回答3:

Simplest solution without fout.Close() should be:

        using (StreamWriter fout = new StreamWriter(saveFileDialog.FileName))
        {
            fout.Write(textBox.Text);
        }

回答4:

If you don't close it, you can't guarantee that it'll write out the last piece of data written to it. This is because it uses a buffer and the buffer is flushed when you close the stream.

Second, it will lock the file as open preventing another process from using it.

The safest way to use a filestream is with a using statement.

回答5:

Short answer, the resources allocated for that operation will not be freed not to mention that it could pottentially lock that file.

回答6:

Consider

using( var fout = new StreamWriter(saveFileDialog.FileName){ fout.write(textBox.Text); }

回答7:

Any how GC will close it for you. But the thing is until the GC closes that stream you are unnecessary putting on hold to the resources

回答8:

You can try with using blok in order to clean your no managed object

        using (var streamWriter = new StreamWriter(saveFileDialog.FileName))
        {
            streamWriter.Write(textBox.Text);
        }

回答9:

It would be a memory hazard.

I would always use StreamWriter in a 'using' statement

using(StreamWriter fout = new StreamWriter(saveFileDialog.FileName)
{
    fout.Write(textBox.Text);
}

来源：https://stackoverflow.com/questions/12783947/what-happens-if-streamreader-or-streamwriter-are-not-closed

标签

streamwriter