Folder picker not working

[dynamiquel]

Describe the bug
When using the PickSingleFolderAsync() method from Windows.Storage.Pickers.FolderPicker. The following exception is given: System.Runtime.InteropServices.COMException: 'Invalid window handle. (0x80070578)'

Steps to reproduce the bug
Use the following code:

var picker = new Windows.Storage.Pickers.FolderPicker();
picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.Desktop;
picker.FileTypeFilter.Add("*");

var folder = await picker.PickSingleFolderAsync();

Expected behavior
The folder picker opens.

Screenshots

Version Info

NuGet package version:
[Microsoft.WinUI 3.0.0-preview2.200713.0]

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2020 Update (19041)
November 2019 Update (18363)	Yes
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context

[eleanorleffler]

I had a similar issue #2716.

[jevansaks]

Duplicate of #2716 (use IInitializeWithWindow to give the owner window).

[manurode]

@jevansaks I'm using IInitializeWithWindow but I'm getting this:

System.UnauthorizedAccessException: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

It's a UWP using Windows.UI.Xaml

[Osaxely]

Same here. On a UWP (Windows.UI.Xaml) app.

[krschau]

@manurode @Osaxely Are you using a WinUI 2 UWP app? The solution jevansaks gave is specific to WinUI 3, where there is no core window. In WinUI 2 the old solutions should work.