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

[Sayed Arian Kooshesh]

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
>
> --
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-- 
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which his computer is programming him.

-Wozniak
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