Do i need to dispose of this Image instance?

Question

Hi folks, I'm making a simple Image Debugger Visualizer. Code is below. I'm not sure if i need to manually dispose of the Image instance? Because i'm making a windows Form window and the PictureBox inside that contains my dynamic image .. do i need to add some special code when the form is terminating, to dispose of this?

here's the code..

using System.Diagnostics;
using System.Drawing;
using System.Windows.Forms;
using Microsoft.VisualStudio.DebuggerVisualizers;
using DebuggerVisualizers;

[assembly: DebuggerVisualizer(
    typeof (ImageDebuggerVisualizer),
    typeof (VisualizerObjectSource),
    Target = typeof (Image),
    Description = "Image Visualizer")]

namespace DebuggerVisualizers
{
    public class ImageDebuggerVisualizer : DialogDebuggerVisualizer
    {
        protected override void Show(IDialogVisualizerService windowService, IVisualizerObjectProvider objectProvider)
        {
            Image image = (Image) objectProvider.GetObject();
            Form form = new Form
                           {
                               Text = ("Image Visualizer - " + image.HorizontalResolution + " " + image.VerticalResolution),
                               Width = image.Width,
                               Height = image.Height
                           };

            PictureBox pictureBox = new PictureBox {Image = image, SizeMode = PictureBoxSizeMode.AutoSize};
            form.Controls.Add(pictureBox);
            form.ShowDialog();
        }
    }
}

thanks for any help :)

Answer 1

The picture box control does not dispose of the image, so this is up to you, yes.

Answer 2

Um, I'm going to go out on a limb here and say you shouldn't dispose of it.

I never created a visualizer, and I don't exactly know Visual Studio does this, but it seems to me that if you dispose of an object in a visualizer, you might break the code you're debugging.

It all comes down to this line:

Image image = (Image) objectProvider.GetObject();

If that object isn't a clone, then you will be disposing the object created by the code that's being debugged. The code won't be expecting that object to be suddenly disposed, and S will hit the fan, causing you at least to have to restart your debugging.

I'd play it safe and NOT dispose of it. Think about it--you're debugging. That's not a long lived process. If you do leak a bitmap handle, its not the end of the world...

Answer 3

I think you should dispose it. It should be quite easy, just add a using() at the first line of your method (around the Image image = ... line) and end it after the form.ShowDialog().

I think it is safe to dispose the image, for if you want to change the visualized object you must call one of the TransferData/TranferObject/ReplaceDat/ReplaceObject methods to send it back.

Answer 4

Change your Show method to this:

protected override void Show(IDialogVisualizerService windowService,
    IVisualizerObjectProvider objectProvider)        
{            
    Image image = (Image) objectProvider.GetObject();
    using (Form form = new Form())
    {            
        PictureBox pictureBox = new PictureBox();    
        pictureBox.Image = image;        
        form.Controls.Add(pictureBox); 
        form.ShowDialog();
    } 
}

The using(){} block will call Dispose on the form after it closes, which will dispose of everything on the form also.