dismiss modal segue..

Objective-C exception thrown. Name: NSGenericException Reason: Could not find a navigation controller for segue 'OnayGiris'. Push segues can only be used when the source controller is managed by an instance of UINavigationController.

this.DismissModalViewControllerAnimated (true);

                            if (Done != null)
                              Done (this, EventArgs.Empty);

should i use this dissmiss before push segue?