Image.ImageOpened Event
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Occurs when the image source is downloaded and decoded with no failure. You can use this event to determine the natural size of the image source.
// Register
event_token ImageOpened(RoutedEventHandler const& handler) const;
// Revoke with event_token
void ImageOpened(event_token const* cookie) const;
// Revoke with event_revoker
Image::ImageOpened_revoker ImageOpened(auto_revoke_t, RoutedEventHandler const& handler) const;public event RoutedEventHandler ImageOpened;function onImageOpened(eventArgs) { /* Your code */ }
image.addEventListener("imageopened", onImageOpened);
image.removeEventListener("imageopened", onImageOpened);
- or -
image.onimageopened = onImageOpened;Public Custom Event ImageOpened As RoutedEventHandler <Image ImageOpened="eventhandler"/>
Event Type
Remarks
When ImageOpened fires, that serves as the notification that any asynchronous operations have completed and all the properties of the object used as the image source are ready for use. For example, to determine the size of the image, handle ImageOpened, and check the value of the PixelWidth and PixelHeight properties on the object referenced as Image.Source. The event data for the ImageOpened event isn't typically useful.
When the Image element isn’t in the live visual tree, the Image element will not fire ImageOpened or ImageFailed events. If you need to receive these events while the element isn’t in the live tree, use the BitmapImage.ImageOpened/ImageFailed events.
Windows 8 behavior
For Windows 8, resources can use a resource qualifier pattern to load different resources depending on device-specific scaling. However, resources aren't automatically reloaded if the scaling factor changes while the app is running. In this case apps would have to take care of reloading resources, by handling the DpiChanged event (or the deprecated LogicalDpiChanged event) and using ResourceManager API to manually reload the resource that's appropriate for the new scaling factor. Starting with Windows 8.1, any resource that was originally retrieved for your app is automatically re-evaluated if the scaling factor changes while the app is running. In addition, when that resource is the image source for an Image object, then one of the source-load events (ImageOpened or ImageFailed) is fired as a result of the system's action of requesting the new resource and then applying it to the Image. The scenario where a run-time scale change might happen is if the user moves your app to a different monitor when more than one is available.
If you migrate your app code from Windows 8 to Windows 8.1 you may want to account for this behavior change, because it results in ImageOpened or ImageFailed events that happen at run-time when the scale change is handled, even in cases where the Source is set in XAML. Also, if you did have code that handled DpiChanged/LogicalDpiChanged and reset the resources, you should examine whether that code is still needed given the new Windows 8.1 automatic reload behavior.
Apps that were compiled for Windows 8 but running on Windows 8.1 continue to use the Windows 8 behavior.