Re: memory leak

I think there's still a misundestanding of the fundamentals.

Dispose is not a required call - it is optional. Your application knows
better than anything else when you are done with resources, and at that
point, you can call Dispose to let the GC know that you are done with those
resources. These classes are written so that during that call, managed
resources are released.

If you don't call Dispose, that's fine. When the GC goes to collect, it
will walk the roots. It will see that the Bitmap has no references, and it
will then run Dispose on it for you and move it to the Finalizer queue. On
the _next_ GC cycle, the actual Bitmap will be released. This all happens
automatically, without your intervention. It just happens late - when the
GC is collecting - likely because you're low on resources.

Calling Dispose is simply a good idea because it allows the release of
system resources when the app is done with them rather than waiting for the
system to GC.

For more info, take a look at my presentation from MEDC:
http://blog.opennetcf.org/ctacke/PermaLink,guid,e806d34b-a8d8-45e8-9de8-bec58818fafe.aspx


--
Chris Tacke
OpenNETCF Consulting
www.opennetcf.com
--




"Hilton" <nospam@xxxxxxxxxx> wrote in message
news:0lMDg.8207$9T3.540@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Chris,

This has come up before, so no use beating a dead horse (I'm the guilty
one here since I first mentioned it), but here are some points which
hopefully helps to explain my comments:

1. If ALL objects were required to be disposed, would that be a design
bug? Of course it would, it is .NET with a garbage collector.
2. Then why do we have to dispose Bitmap? Because MS took a short-cut.
Note that MS have already said that they will *fix* this problem.
3. Another bad choice IMHO was to put Bitmap in System.Drawing - that is
the wrong place since you don't only draw with Bitmap and a Bitmap image
should not be directly associated with UI. It should be in System.Image
or something similar. Here is an example in pseudo-C#: Imagine you wanted
to convert all BMP files to PNG files using a command line EXE. It should
simply be "using System.Image; foreach BMPFile in directory { new Bitmap
(BMPFile).SaveAs (PNG); }" but instead we have to include System.Drawing
(UI stuff), plus we need to do our own memory management (the code above
would have a huge memory leak).
4. FWIW: I think Dispose should be an optional call, not a mandatory call
required to prevent a memory leak.
5. There are other things like why they called it SortedList instead of
SortedMap etc... (unrelated to Bitmap)

Bottom line, I love C#, work with it day in and day out, absolutely darn
amazing on Pocket PCs etc, so don't think for a second I'm bashing the C#
language, the .NET team, or Microsoft. Just sometimes, bad design
decisions get made (*IHMO*).

Hilton


"<ctacke/>" <ctacke[@]opennetcf[dot]com> wrote in message
news:eWyovzwvGHA.3372@xxxxxxxxxxxxxxxxxxxxxxx
The same has to be done on the full framework, and again, it's not a bug.

-Chris


"Hilton" <nospam@xxxxxxxxxx> wrote in message
news:gvJDg.12218$gY6.3863@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I bet you're doing something like "xyz.Image = new Bitmap (...)" - right?
If so, there is a bug in the CF design/implementation (IMHO) that forces
you to do your own memory management; i.e. for every "new Bitmap ()" you
do, you'll need to do a "Dispose()" on that bitmap when you're done with
it (aka malloc and free).

Let us know if that helps,

Hilton


"raju" <ponnurajs@xxxxxxxxx> wrote in message
news:1155390117.643466.283160@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hai

In my device application (windows ce application using vb.net), i
am having nearly 25 forms. Moving from one form to another form, just i
am hide the first form and show the second form.

Each form I am having some picturebox, putting images for that
picturebox using imagelist.

My application works very well. But, if the application running
contineously for 1 or 2 hours, i am getting error such as "low memory".


when i checked the memory, it will automatically increasing when
the application is in running. First initial time, it occupies 22 mb
and it increasing upto 32 to 35 mb.

What is the reason for this? and how to correct this memory
problem.

Regards
Raju.









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Relevant Pages

  • Re: memory leak
    ... explicit GC and it worked just as it should - memory climbed up to near 2GB ... Now do you still agree that the GC will cleanup Bitmap objects? ... Dispose is not a required call - it is optional. ... those resources. ...
    (microsoft.public.dotnet.framework.compactframework)
  • Re: memory leak
    ... I am pretty diligent when it comes to disposing unmanaged resources. ... If an OOM occurs when attempting to create a bitmap from a binary ... making it appear that the device has more available memory. ... Dispose is not a required call - it is optional. ...
    (microsoft.public.dotnet.framework.compactframework)
  • Re: memory leak
    ... Adding GC.Collectcauses the memory to drop, ... Now do you still agree that the GC will cleanup Bitmap objects? ... Dispose is not a required call - it is optional. ... those resources. ...
    (microsoft.public.dotnet.framework.compactframework)
  • Re: memory leak
    ... explicit GC and it worked just as it should - memory climbed up to near ... Now do you still agree that the GC will cleanup Bitmap objects? ... Dispose is not a required call - it is optional. ... done with those resources. ...
    (microsoft.public.dotnet.framework.compactframework)
  • Re: memory leak
    ... explicit GC and it worked just as it should - memory climbed up to near ... Now do you still agree that the GC will cleanup Bitmap objects? ... Dispose is not a required call - it is optional. ... those resources. ...
    (microsoft.public.dotnet.framework.compactframework)