Monotouch - Issue with QLPreviewController - ios

Question

I am trying to use QLPreviewController to see a PDF file and send it, but I have an issue with the action button after previewing the PDF document.
When I press the action button (at the top right) app crashes and I get: "Unhandled managed exception: Objective-C exception thrown. Name: NSInternalInconsistencyException Reason: UIDocumentInteractionController: invalid scheme (null). Only the file scheme is supported. (MonoTouch.Foundation.MonoTouchException)"
I did some research and it seams that this issue may occur if you download a file from the internet or if the file type is not "file:// .......... ".
My NSUrl is on that format so I dont know why I have this error.
Anybody has any idea?
Thanks
Here is my code to call the Controller:
QLPreviewController previewController= new QLPreviewController();
previewController.DataSource=new MyQLPreviewControllerDataSource();
this.PresentViewController(previewController,true, null);
This is my code for the DataSource:
public class MyQLPreviewControllerDataSource : QLPreviewControllerDataSource { public override int PreviewItemCount (QLPreviewController controller) {
return 1;
}
public override QLPreviewItem GetPreviewItem (QLPreviewController controller, int index)
{
string fileName = #"example.pdf";
var documents = Environment.GetFolderPath (Environment.SpecialFolder.MyDocuments);
var library = Path.Combine (documents,fileName);
NSUrl url = NSUrl.FromFilename (library);
return new QlItem ("Title", url);
}
}
This is my code for the item:
public class QlItem : QLPreviewItem { string _title; Uri _uri;
public QlItem (string title, Uri uri)
{
this._title = title;
this._uri = uri;
}
public override string ItemTitle {
get { return _title; }
}
public override NSUrl ItemUrl {
get { return _uri; }
}
}

Answer 1

Your QlItem class is casting the original NSUrl into a Uri before casting it back into a NSUrl and something is getting lost along the way.
It should look more like:
public class QlItem : QLPreviewItem
{
string title;
NSUrl uri;
public QlItem(string title, NSUrl uri)
{
this.title = title;
this.uri = uri;
}
public override string ItemTitle {
get { return title; }
}
public override NSUrl ItemUrl {
get { return uri; }
}
}