System.UnauthorizedAccessException on File.OpenRead

Question

I'm making a Windows Phone 8.1 Silverlight, and when I try to read a file, and upon reading, the following error occurs:

An exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.ni.dll but was not handled in user code

Additional information: Access to the path 'C:\Data\Users\Public\Pictures\Camera Roll\WP_20150421_001.jpg' is denied.

{
    string filepath = FilePathTextBox.Text;
    string cryptPath = filepath;
    File.SetAttributes(cryptPath, System.IO.FileAttributes.Normal);

    FileStream stream = File.OpenRead(cryptPath);
    byte[] fileBytes = new byte[stream.Length];

    stream.Read(fileBytes, 0, fileBytes.Length);
    stream.Close();

    byte[] ProtectedFileBytes = ProtectedData.Protect(fileBytes, null);
    using (Stream file = File.OpenWrite(@"C:\Data\Users\Public\Documents"))
    {
        file.Write(ProtectedFileBytes, 0, ProtectedFileBytes.Length);
    }
    MessageBox.Show("File Sucessfully Encrypted");
}

All of the relevant libraries are checked in the manifest, I'm running Visual Studio as administrator, I've tried different files, all to no avail.

I added a check to verify if the file exists, and that flagged as false, but that is likely due to the permissions problem.

Any suggestions as to solving this problem?

Edit: I now have this code, which is throwing a System.ArgumentException:

private async void EncryptButton_Click(object sender, RoutedEventArgs e)
    {
        string filepath = FilePathTextBox.Text;
        string cryptPath = filepath;

        await FileOps();
            FileStream stream = File.OpenRead(cryptPath);
            byte[] fileBytes = new byte[stream.Length];

            stream.Read(fileBytes, 0, fileBytes.Length);
            stream.Close();

            byte[] ProtectedFileBytes = ProtectedData.Protect(fileBytes, null);
            using (Stream file = File.OpenWrite(@"C:\Data\Users\Public\Documents"))
            {
                file.Write(ProtectedFileBytes, 0, ProtectedFileBytes.Length);
            }
            MessageBox.Show("File Sucessfully Encrypted");
    }

    private async Task FileOps()
    {
        string filepath = FilePathTextBox.Text;
        string cryptPath = filepath;
        StorageFolder storageFolder = KnownFolders.CameraRoll;
        StorageFile file = await storageFolder.CreateFileAsync(cryptPath, CreationCollisionOption.ReplaceExisting);
    }

bdimag bdimag · Accepted Answer · 2015-04-21T17:26:33

I think the issue here is that you cannot simply access by path... You will need to go through the known folders:

KnownFolders class

Quickstart: Working with files and folders in Windows Phone 8

// Get the folder.
StorageFolder camera = Windows.Storage.KnownFolders.CameraRoll;

if (local != null)
{

    // Get the file.
    var file = await camera.OpenStreamForReadAsync("WP_20150421_001.jpg");

    // Read the data.
    using (StreamReader streamReader = new StreamReader(file))
    {
        //streamReader.ReadToEnd();
    }

}

System.UnauthorizedAccessException on File.OpenRead

1 Answers