[mono-android] Not catching null reference - why?

[Sayed Arian Kooshesh]

the as syntax checks to see if it can be properly null, then instead of
throwing an exception (so memory haevy) just returns a null. So beautifyl.


Drunk. Idk. I just love code. Send me your code I will see if I can't draw
my divine being on to it.

On Thu, Jun 21, 2012 at 5:56 AM, Sayed Arian Kooshesh <kooshesh at gmail.com>wrote:

>
> correct syntax is:
> if( (reference.Target as Bitmap) ==null)
>
>
>
>
>
> On Thu, Jun 21, 2012 at 2:42 AM, bjarke <jbp at itai.dk> wrote:
>
>> Hey guys
>>
>> I have a list of bitmaps with weak references however sometimes the bitmap
>> is null. This is okay and as expected however my issue is that it does not
>> work doing a check against null. This is my method;
>>
>>  public static Bitmap DecodeFile(string _path)
>>        {
>>            WeakReference reference;
>>            var options = new BitmapFactory.Options {InPreferredConfig =
>> Bitmap.Config.Rgb565};
>>            Bitmap image=null;
>>            //refs is a dictionary of Dictionary<string, WeakReference>
>>            if (refs.TryGetValue(_path, out reference))
>>            {
>>                    if (reference.IsAlive)
>>                    {
>>                        image = (Bitmap)reference.Target;
>>
>>                        if (image==null)
>>                        {
>>                        // image has been garbage collected
>>                        // remove reference from cache
>>                            refs.Remove(_path);
>>                        }
>>                        else
>>                        {
>>
>>                            return image;
>>                        }
>>
>>
>>                    }
>>                    else
>>                    {
>>                        // image has been garbage collected
>>                        // remove reference from cache
>>                        refs.Remove(_path);
>>                    }
>>
>>                }
>>            image = BitmapFactory.DecodeFile(_path, options);
>>            reference = new WeakReference(image);
>>            refs.Add(_path, reference);
>>            return image;
>>        }
>>
>> The check if(image==null) is false even though it is null. If I do a
>> image.Equals(null) I get a nullpointer exception instead. So right now I
>> catch the exception instead and handle it - however I really do not like
>> that approach.
>>
>> Any suggestion is well recieved :)
>>
>> Regards Bjarke
>>
>> --
>> View this message in context:
>> http://mono-for-android.1047100.n5.nabble.com/Not-catching-null-reference-why-tp5710468.html
>> Sent from the Mono for Android mailing list archive at Nabble.com.
>> _______________________________________________
>> Monodroid mailing list
>> Monodroid at lists.ximian.com
>>
>> UNSUBSCRIBE INFORMATION:
>> http://lists.ximian.com/mailman/listinfo/monodroid
>>
>
>
>
> --
> Extreme Knowledge is not something for which he programs a computer but
> for which his computer is programming him.
>
> -Wozniak
>



-- 
Extreme Knowledge is not something for which he programs a computer but for
which his computer is programming him.

-Wozniak
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ximian.com/pipermail/monodroid/attachments/20120626/23e1503d/attachment-0001.html>