ItemSelected not called - Xamarin.iOS F#

I have a UICollectionViewController defined as follows:

    [<Register ("LandlordHome")>]
type LandlordHome (handle:IntPtr) = 
    inherit UICollectionViewController (handle)


    override x.ViewDidLoad () =
        base.ViewDidLoad ()

        let collectionViewDelegate = new CollectionViewFlowDelegate(new IntPtr())
        collectionViewDelegate.parent <- x

        x.CollectionView.Delegate <- collectionViewDelegate

I omitted irrelevant code for clarity.

Next, I have a UICollectionViewDelegateFlowLayout defined as follows:

    [<Register ("CollectionViewFlowDelegate")>]
type CollectionViewFlowDelegate (handle:IntPtr) = 
    inherit UICollectionViewDelegateFlowLayout (handle)

    let mutable parentViewController : UIViewController = null

    member this.parent 
        with get() = parentViewController 
        and set(value) = parentViewController <- value

    override x.ItemSelected(collectionView : UICollectionView, indexPath : NSIndexPath) = 
        let controller = new ChatControllerLandlord(new IntPtr())
        controller.GetListingId <- ""
        controller.GetPartnerId <- ""
        controller.GetLandlordId <- ""
        controller.GetPartnerName <- ""
        parentViewController.PresentViewController(controller,true,null)

This is done in order to override the ItemSelected method so that when I tap on the UICollectionViewCell the code inside of it is executed.

However, when I tap on the cell nothing happens.

I tried your code , found the workaround.

Modify the construction method of CollectionViewFlowDelegate as below:

let collectionViewDelegate = new CollectionViewFlowDelegate()
collectionViewDelegate.parent <- x
x.CollectionView.Delegate <- collectionViewDelegate


type CollectionViewFlowDelegate () = 
inherit UICollectionViewDelegateFlowLayout ()