C＃/ XAML-字符串到图像源的转换

Question

Hoping I can get some opinions on the issue I'm having. First, I'll explain that I did try suggestions from other answers of questions that are similar to what I'm experiencing, but without any luck.

The objective is to take a string and convert it to a path for an image element in my XAML code. Similar to how you can adjust a textblock's "text" property in the code-behind file with something like this,

courseFaculty.Text = BL_PageContent.FacultyMember;

in which FacultyMember is a property from the associated BL_PageContent.cs file, I'd like to do the same but provide a string for the image's path.

Here's my XAML for my image, which renders a blank "placeholder," if you will:

<Image x:Name="courseFacultyPic" HorizontalAlignment="Center" VerticalAlignment="Top" Margin="246,127,10,0" Height="117" Width="104"></Image>

Testing this more "manually," I've entered the source path as a Source property and had success:

<Image x:Name="courseFacultyPic" HorizontalAlignment="Center" VerticalAlignment="Top" Margin="246,127,10,0" Height="117" Width="104" Source="facultyProf1.jpg"></Image>

Using something that was suggested to me OUGHT to render the image I intend into this "placeholder:"

string facultyPicPath = "collegeProf1.jpeg";
Uri imageUri = new Uri(facultyPicPath);
BitmapImage facultyImage = new BitmapImage(imageUri);
Image courseFacultyPic = new Image();
courseFacultyPic.Source = facultyImage;

This code block above would initiate from a user clicking a UI control. When I try it, though, I get a runtime exception regarding the line where I am instantiating the Uri class. The runtime exception is as follows:

An exception of type 'System.UriFormatException' occurred in System.Private.Uri.dll but was not handled in user code Additional information: Invalid URI: The format of the URI could not be determined.

Any thoughts/suggestions/opinions welcome. This is my first post and my first experience handling images within my app, and am self-taught, so please take that into consideration. Many thanks!

Answer 1

This is because XAML has built in converters to take the image name like that and set it as an image source. When you use new BitmapImage(imageUri) you should specify the full image path.

If you are using WPF you can use the ImageSourceConverter but I don't believe this is available for UWP apps. I'm not sure... However; it's not to hard to write your own once your own.

https://msdn.microsoft.com/en-us/library/system.windows.media.imagesourceconverter.convertfromstring(v=vs.110).aspx

Answer 2

I ever got that error too. The solution is you must specify manually what kind of URI is that. From my experience, assuming that you have added the image to the project in the same directory as the application source code files, the URI kind you must specify is UriKind .Relative .

In the Uri constructor, specify it in the second parameter like this:

Uri imageUri = new Uri(facultyPicPath, UriKind.Relative);

Answer 3

Here's the solution to my problem. Thanks to Rizki !

The given System.Uri cannot be converted into a Windows.Foundation.Uri