Thanks for your reply and hanging in there on this extremely puzzling failure of UriKind.Relative. I did as you said, adding an ImageFailed handler to the image. When I set image.Source to the BitmapImage however, The ImageFailed event did not occur. The image simply did not show up in the window containing the image.
What I want to do is set the window Width and Height based on the PixelWidth and PixelHeight of the BitmapImage (taking into consideration the window border width and window option height -- irrelevant details). But the effort to get PixelWidth and PixelHeight causes an exception, in the following code:
As you can see, I set a default width and height to 450x300, just so the window shows up at all, but it shows up empty. string error in the exception handler says this (slightly simplified so just so you get the idea that it is looking at a path in my source code rather than a path in my project assembly):
"Could not find a part of the path 'C:\\...\\bin\\Debug\\Images\\screenshot.png'."
I did exactly the same thing you did in your example. I put a .png file in a folder off the project called Images, made sure its BuildAction was Resource, then tried to look at the BitmapImage.PixelWidth (which I needed to size the window exactly that was to contain the image). I got an exception that reported that it "couldn't find part of the path", and it quoted a path something like, "C:\...\bin\Debug\Images\Airplane.png". Then when I set the image Source to the BitmapImage I got no exception and when I hovered over the image.Source code in the debugger, it showed a URI something like this:
I'm not sure what's happening on your end, but you
shouldn't be getting any paths like "C:\...\bin\Debug\Images\Airplane.png",
since that is NOT a pack uri for extracting a resource image.
As far as getting PixelWidth/PixelHeight, that could be tricky.
For example, with the following code:
myimage.ImageFailed += new EventHandler<ExceptionRoutedEventArgs>(myimage_ImageFailed);
Uri uri = new Uri("/Images/Airplane.png", UriKind.RelativeOrAbsolute);
BitmapImage bi = new BitmapImage();
bi.UriSource = uri;
myimage.Source = bi;
with a breakpoint on "myimage.Source = bi;", bi.PixelWidth/bi.PixelHeight
are 0, and also having the breakpoint there causes the image to not appear.
Put a breakpoint after "myimage.Source = bi;" (removing the
previous breakpoint!) and bi.PixelWidth/bi.PixelHeight are valid (but
is that just lucky timing?).
It appears the decoding is asynchronous, and I see no event for
Your statement about getting pixel dimensions could be tricky was all the hint I needed. The problem was I was executing the following statement last in my Loaded event:
image.Source = screenshot;
and immediately after the following statement
BitmapImage screenshot = new BitmapImage(uri);
I was getting the pixel dimensions of the image:
// Get the pixel dimensions of the image so we can size the window properly.double imageWidth = 450;
double imageHeight = 300;
imageWidth = screenshot.PixelWidth;
imageHeight = screenshot.PixelHeight;
catch (Exception ex)
string error = ex.Message;
Apparently the very act of asking for the pixel dimensions somehow corrupted the screenshot BitmapImage object. When I moved image.Source = screenshot; from the end of the event to the statement immediately following the BitmapImage constructor, UriKind.Relative started working! Apparently using an absolute pack URI provided enough of a delay to complete the asynchronous decoding.
I hope this explanation is clear. If it isn't, I could make another post showing all of the code for the Loaded event. Thank you very much for sticking with me on this issue.
I still hope they add a proper event like they did for
Silverlight, in which they added ImageOpened events to both
the BitmapImage and Image classes, specifically to get a look
at the loaded bitmap's dimensions before rendering.
Getting lucky with timing worries me, although in this case
maybe there's some mechanism forcing the decoding of the image
at that instance. I haven't seen that confirmed in any docs though
I'm working on learning WPF, and I'm having an issue with my menu. The menu displays fine but when I click on a root level item, the sub menu does not appear to drop down. It still appears that I can click on where the menu item should be, and it will fire the proper event. Is there something common errors that cause this or do i need to post some source code because I'm doing something dumb?
Ennis Ray Lynch, Jr. wrote:
Unpaid overtime is slavery.
Meetings - where minutes are taken and hours are lost.
I need to find the binding control of my TreeViewItem's parent, GetContainerFromItem gives me the parent TreeViewItem and GetParent gives me the Parent Item, but how do I get the control that is bound to the parent Item?
I'm using a custom control to display the items, and need to manipulate it from a child control...
Be brave little warrior, be VERY brave
In my silverlight application I've many pages(1,2,3...), after logged in i'm showing default page. After that if i click on any page default loading (silverlight progress like rotating a default logo with continual increment of time) is going on.
Next if i click on the any other page of same page that silverlight progress is not showing. My silverlight pages have huge data, so for loading the data it takes time to show any page without showing any progress.
I need to show any progress bar on loading the data.... is it possible to show the progress bar in all pages while loading?
1) Before you request data, show a ProgressBar.
2) If you're using a data retrieval method that reports download status, update the ProgressBar.
If no download status is available, you could set the ProgressBar's IsIndeterminate property to True.
3) When the data is received, hide and/or remove the ProgressBar.