Bug: Cannot launch folder pickers in LowIL mode (partial trust)

[HEIC-to-JPEG-Dev]

Description

When running a WinUI 3 app in lowIL mode (as UWP does), you cannot call he folder pickers.

System.UnauthorizedAccessException when trying to use WinRT.Interop.InitializeWithWindow.Initialize(folderPicker, hwnd);

This is because hwnd is not allowed in LowIL mode.

This prevents UWP migration.

Steps To Reproduce

WinRT.Interop.InitializeWithWindow.Initialize(folderPicker, hwnd);

Expected Behavior

This line is only required because of the implementation of the MainWindow and is for interrop. But doesn't provide for the high security requirements of LowIL mode.

I expect he pickers to launch

We know this doesn't work for admin mode (privelaged access) either and the WASDK team have created a new API specifically for that. But that new API also doesn't work in low privelage mode.

Version Info

WASDK 1.7
csWinRT 2.2

Additional Context

No response

[dongle-the-gadget]

This is not a CsWinRT bug. This is a Windows limitation. You can do the exact equivalent in C++/WinRT and see the exact same error.

[HEIC-to-JPEG-Dev]

So what you're saying is no UWP app can migrate to WinUI and keep the security model - they have to move to MediumIL ?

[dongle-the-gadget]

Depends on their needs, but MediumIL tends to be the supported option.

[HEIC-to-JPEG-Dev]

Problem is, MediumIL impacts the performance of the Windows.Storage API's, making them 7x slower, so I can't imaging anyone going "Hey, we migrated to WinUI, sorry the performance is so bad now"