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Are you trying to play the mp3 file that you added to the Assets folder? If it is, then the issue is caused by your URI.
You could not pass the file path parameter to CreateFromUri directly. In general, the Uri parameter is HTTP protocol address such as http://www.xxx.com/xxx/test.mp4
. But you could assign some the file path with UWP file access URI scheme.
If you want to access the Assets folder in your project, you could try to use the following Uri:
var soundPath = "ms-appx:///Assets/xxxxxx/xxx.mp3";
Thank you.
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