Writing to Text File

Question

I'm having trouble with what seems like it should be simple but I just can't get it to work.  Here are the facts:

- I'm using the Dashboard service with Eddie.

- I wrote some code in the Depth cam form that for each time a depth cam image is displayed on the form, it will also save the image to a file and also write a line to a text file for the encoder data.  Here's the code:

public void SaveToVideo(int width, int height, short[] depthData, int leftencoder, int rightencoder)

        {
            Bitmap bmp = MakeDepthBitmap(width, height, depthData);
            Image<Bgr, byte> cvImage = new Image<Bgr, byte>(bmp);

            try
            {
                counter++;

                if (counter % 3 == 0)
                {

                    sw.WriteLine("{0}   {1} {2}", counter, leftencoder, rightencoder);
                    cvImage.Save("DC" + counter.ToString() + ".bmp");
                }

            }
            catch (Exception e)
            {
                Console.WriteLine("save2: " + e.Message);
            }
            finally
            {
                bmp.Dispose();
            }
        }

- All the code related to saving an image works fine (it actually uses an OpenCV wrapper called EmguCV for this.

- The code related to writing to a text file does not work at all.  Essentially, I have the following code when the form opens: 

sw = new StreamWriter("encoder_data.txt", false);

- This code creates a blank text file but is never updated with new data.

- At first I thought this is a threading issue but then I used the CCR code which I found here: http://blogs.msdn.com/b/pollrobots/archive/2008/07/22/ccr-utilities-part-1.aspx.  That too did the same thing after I made the necessary changes.

Any help would be appreciated.

Dan.

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Dan Sionov

Answer 1

Could it be simply that buffered writes are never making it to disk? Try adding a sw.Flush() somewhere appropriate (or even after every write).

Another alternative, which is used in Paul’s blog post you mention, would be to create with appending and flush/dispose on every write as in:

using (var sw = new StreamWriter(…, true)) { sw.WriteLine(…); }

Hope that helps!

Answer 2

You called it.  I just set sw.Autoflush = true and that did the trick.

Thank you!!

Dan.

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Dan Sionov