How to access downloaded sound in IsolatedStorage via URI (WP8)? - windows-phone-8

Question

I am struggling with this problem of accessing the sound file (mp3) download in isolated storage to be used in Alarm ,
The problem mentioned before
I am getting this error:
BNS Error: The action request's sound uri is invalid
Please help me but remember I am using the sound file for Alarm
Regarding the code it is the same as the link above.
This is download and save code of the sound file :
Public Async Function DownloadFile(url As Uri) As Task(Of Stream)
wc = New WebClient()
AddHandler wc.OpenReadCompleted, AddressOf OpenReadCompleted
AddHandler wc.DownloadProgressChanged, AddressOf DownloadProgress
wc.OpenReadAsync(url)
Dim r As IO.Stream = Await tcs.Task
Return r
End Function
Private Sub OpenReadCompleted(sender As Object, e As OpenReadCompletedEventArgs)
If e.[Error] IsNot Nothing Then
tcs.TrySetException(e.[Error])
ElseIf e.Cancelled Then
tcs.TrySetCanceled()
Else
tcs.TrySetResult(e.Result)
Dim file As IsolatedStorageFile
file = IsolatedStorageFile.GetUserStoreForApplication()
Using Stream As IsolatedStorageFileStream = New IsolatedStorageFileStream("Sound.mp3", System.IO.FileMode.Create, file)
Dim buffer As Byte() = New Byte(1023) {}
While (e.Result.Read(buffer, 0, buffer.Length) > 0)
Stream.Write(buffer, 0, buffer.Length)
End While
End Using
End If
End Sub
Private Sub DownloadProgress(sender As Object, e As DownloadProgressChangedEventArgs)
Proind.Value = e.ProgressPercentage / 100
Proind.Text = e.ProgressPercentage.ToString & " %" & " ( " & (e.BytesReceived \ 1000).ToString & "/" & (e.TotalBytesToReceive \ 1000).ToString & " ) KB"
End Sub

Answer 1

The problem is that you are trying to set a file in the isolated storage as the sound of the alarm, and that's not allowed. Only files packaged in .xap can be set as sound source of the alarm:
Remarks
The Sound URI must point to a file packaged in the application’s .xap
file. Isolated storage is not supported. When the alarm is launched,
the sound is played quietly and then gradually increases in volume.
There is no way to modify this behavior.
From:
Alarm.Sound Property
However, there is a way you could use a downloaded song as alam's sound. In OpenReadCompleted method, instead of saving the downloaded file in the isolated storage, create a file using File.Create method, and store the data there. Then it will be possible to use this file as the alarm sound:
Here is the C# code, I think you will easily translate to VB:
byte[] buffer = new byte[e.Result.Length];
e.Result.Read(buffer, 0, buffer.Length);
using (var fs = File.Create("file.mp3"))
{
fs.Write(buffer, 0, buffer.Length);
}
Then, you can set the Sound property of the alarm as:
alarm.Sound = new Uri("/file.mp3", UriKind.Relative);