Appending text to a line in a listbox
<p>Is there a way to append text to the last line in a ListBox? I'd like a listing to look like this:</p>

<pre><code>processing file 1...  OK
processing file 2...  CRC error
processing file 3...  OK
</code></pre>

<p>When I open the file for processing, I would write "processing file x" with ListBox.Add("processing file x"). When done processing, before moving on to the next file, I would like to append the processing results. </p>

<p>I could wait until processing is complete, and just write the whole line at once, but it can take 10-15 seconds to process a file and it makes the UI look unresponsive.  </p>

<p>A solution would also let me append text like (% complete) or something to make the UI more active while processing.  I prefer to do this with a ListBox because of its scrolling and line selection properties, if possible.</p>

<p>I've not been able to find any way to do this; any ideas would be welcome.</p>