On 06/07/2010 15:59, Jan-Philip Gehrcke wrote:
Hello,
I don't know if this is more an IronPython (2.6.1) issue than a
Silverlight (4) issue, but I hope that I am talking to the right
audience again (thank you for the great answers last time).
I've created an `Image` class managing images based on
System.Windows.Media.Imaging.BitmapImage. My method
`image_instance.load_and_show()` should load the image from a given
URI and then show it in an XAML <image /> element. The important thing
is that the showing part should only happen after it is sure that the
image has loaded correctly. To control this, I use the
BitmapImage.ImageOpened event. This is the relevant part of the code
from my `Image` class:
def load_and_show(self):
self.bi = BitmapImage(Uri(self.abspath, UriKind.Absolute))
self.bi.ImageOpened += self.successfully_loaded_now_show
self.bi.ImageFailed += self.load_failed
#self.xaml_main_image.Source = self.bi # LINE A
def successfully_loaded_now_show(self, s, e):
debug("image loaded: %s" % s.UriSource) # LINE B
self.xaml_main_image.Source = self.bi # LINE C
def load_failed(self, s, e):
debug("image load failed") # LINE D
If the code is like shown above and I do
`image_instance.show_and_load()`, nothing happens. More exactly, LINE
B, C, and D are not reached. It is like *neither the event ImageOpened
nor ImageFailed is toggled*.
It seems likely then that the image is not opened or downloaded until
you set it as the source on an image. Does the code behave differently
if you write it in C#?
If you set the bitmapimage as the image source does the event then fire
correctly? If so perhaps create the image control but only add it to the
visual tree once the bitmap has loaded.
Michael
If I re-activate (or un-outcomment =)) LINE A, the callbacks magically
work properly, i.e. after calling `image_instance.show_and_load()` the
image shows up in the UI (either via LINE A or C), and LINE B is
definitely reached (or LINE D in case of a wrong URI).
The point is that I don't want LINE A, because showing the image
should happen in a more controlled manner. What's the problem in my
approach, why are the callbacks not called?
Thank you in advance,
Jan-Philip Gehrcke
--
http://gehrcke.de
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