c# WPF URI syntax

3
votes

I am just learning c# and have been struggling to work with URIs in WPF. I've googled around a fair bit but not having much luck.

Essentially I'm trying to have a BitmapImage object stored as a property in a Car object. I then want to display the BitmapImage in an Image control on a WPF form.

The app is a simple app (it's for a Uni assignment), so no database, etc.

I have two methods of doing this. The first is that I'm preloading Car data from a text file, including the filename of the JPG I want to load. I have included the JPG in a directory called Files which is off the main directory where my source code and class files are. I have set the JPG file to 'Content' and 'Always copy'. When I run a Debug, it copies the Files directory and the JPG to the debug\bin directory.

My code creates a BitmapImage by referring to the JPG using a URI as follows;

BitmapImage myImage = new BitmapImage (new Uri("Files/" + Car.Imagefilename, UriKind.Relative);
Car.Image = myImage;
ImageControl.Source = myImage;

If I step through this code in the debugger, it sometimes works and displays the image, but most of the time it doesn't.

My second method is when a user creates a new Car. This method always works. In this one, I use a file dialog box (dlg) to select the image and use an absolute path.

BitmapImage myImage = new BitmapImage (new Uri(dlg.Filename, UriKind.Absolute);
Car.Image = myImage;
ImageControl.Source = myImage;

So....I can't work out why the first method doesn't work. I think it's got something to do with the relative reference, but I can't work out how to syntax that properly to work. I've tried using "pack:,,,", I've tried adding "component", I've tried an '@' before the "pack". I can't seem to find something that explains this simply.

Apologies if this is straight forward but it's doing my head in! Appreciate any pointers.

2
c#wpf

2 Answers

2
votes

First try to load the image file using its absolute path. For example if the images are stored in c:\projects\yourproject\files, then try using something like 

BitmapImage myImage = new BitmapImage (new Uri("c:/projects/yourproject/files/carname.jpg", UriKind.Absolute);

If it works, what you are facing is an path calculation issue.

At this point you may either calculate the Absolute with reference to your executable using AppDomain.CurrentDomain.BaseDirectory at runtime or use App.Config to store the path and reference it from there.

Cheers

8
votes

If the image files are located in a "Files" folder of your Visual Studio project, you should set their Build Action to Resource (and Copy to Output Directory to Do not copy), and load them by a Resource File Pack URI:

var image = new BitmapImage(new Uri("pack://application:,,,/Files/" + Car.Imagefilename));
Car.Image = image;
ImageControl.Source = image;

There is no need to copy the files anywhere. Images are loaded directly from the assembly.