What is the proper way of changing current UIViewController without a memory leak in MonoTouch?

I have a base UINavigationController class ( xib-less code ) using the singleton pattern with the fallowing code

[MonoTouch.Foundation.Register("NavController")]
public class NavController : UINavigationController
{
    public static NavController Instance = new NavController();


    public void ChangePage( UIViewController sender, UIViewController page, double duration )
    {
       this.PopViewControllerAnimated(true);
       this.PushViewController( page, false );
       //
       SetViewControllers( new UIViewController[]{ page }, false );
       if( sender != null )
       {
          sender.View.RemoveFromSuperview();
          sender = null;
       }
       GC.Collect();
    }
}

And also i have 4 UIWebController classes with this structure

[Register("HomePage")]
public class AViewPage : UIViewController
{
    UIButton    btn = new UIButton( new RectangleF( 0,0, 100, 100) );
    UIImageView img = new UIImageView( new RectangleF( 100, 100, 200, 200 ); 
    //and a lot of other widgets

    public override void ViewDidLoad ()
    {
         base.ViewDidLoad ();       
         //
         btn.TouchUpInside += delegate{
             AnotherViewPage page = new AnotherViewPage();
             NavController.Instance.ChangePage( this, page,  1 );
         }
     //
     this.View.AddSubview( btn );
     this.View.AddSubview( img );       
    }

}

My problem is that with current code, memory is leaking. What am I doing wrong?

• Should i override the Dispose(bool) and manually dispose everything on the UIWebController classes ?
• I also have a lot of UIImages and UIImageViews on this UIViewControllers, what is the proper way of disposing them ?
• I have the feeling that the ChangePage function code i开发者_运维问答s ugly. Help me with a better example please.

A fix is coming in the MonoTouch 4.1 beta release, a temporary workaround is this:

Replace this line:

      sender.View.RemoveFromSuperview();

With:

      var super = sender.View.Superview;
      sender.View.RemoveFromSuperview ();
      var scratch = super.Subviews;

The correct fix in the next release will just work. Apologies for that.

Ok, stupid question from the beginning.

If you run in to the same problem, just read a little about PushViewController, PopViewControllerAnimated, ViewDidAppear, ViewDidDisappear and ViewDidLoad.