IncrementalLoadingCollection assumes setting HasMoreItems to true in RefreshAsync will start a reload and does not work

[ettiennehugo]

Describe the bug

IncrementalLoadingCollection::RefreshAsync does not refresh when it's working with a keyed IIncrementalSource. The source will not produce items the first time GetPagedItemsAsync is called, once its key properties are set it will call RefreshAsync - this does not produce a call to GetPagedItemsAsync. It looks like the collection locks _mutex and never unlocks it under certain states so the collection becomes unresponsive.

UPDATE: I implemented the ISupportsIncrementalLoading in my own collection and model view, what I THINK happens is that the flag used to indicate that a reload should occur in the LoadMoreItemsAsync causes a deadlock on the refresh when the RefreshAsync is called from different threads, this can typically happen when the collection is already loading and there are AsyncRelayCommands firing off another RefreshAsync. To debug put some trace logs into the code and trace the thread ID. If this is correct, the simplest approach would be to remove the ?refreshOnLoad? flag and never enter the RefreshAsync when another load is already underway.

Steps to reproduce

Tie an IncrementalLoadingCollection to a ListView
The IIncrementalSource needs specific state before it can load items so ignore the first few calls to GetPagedItemsAsync - e.g. a view model that requires properties that represent keys to be set before it will start providing items.
Set the IIncrementalSource into a correct keyed state and make it call RefreshAsync when that state is achieved - you'll see no new items will be added to the incremental collection.

Expected behavior

Calling RefreshAsync should guarantee a refresh call to GetPagedItemsAsync starting at PageIndex 0.

Screenshots

No response

Code Platform

• [ ] UWP
• [X] WinAppSDK / WinUI 3
• [ ] Web Assembly (WASM)
• [ ] Android
• [ ] iOS
• [ ] MacOS
• [ ] Linux / GTK

Windows Build Number

• [ ] Windows 10 1809 (Build 17763)
• [ ] Windows 10 1903 (Build 18362)
• [ ] Windows 10 1909 (Build 18363)
• [ ] Windows 10 2004 (Build 19041)
• [ ] Windows 10 20H2 (Build 19042)
• [ ] Windows 10 21H1 (Build 19043)
• [ ] Windows 10 21H2 (Build 19044)
• [ ] Windows 10 22H2 (Build 19045)
• [ ] Windows 11 21H2 (Build 22000)
• [ ] Other (specify)

Other Windows Build number

No response

App minimum and target SDK version

• [ ] Windows 10, version 1809 (Build 17763)
• [ ] Windows 10, version 1903 (Build 18362)
• [ ] Windows 10, version 1909 (Build 18363)
• [ ] Windows 10, version 2004 (Build 19041)
• [ ] Windows 10, version 2104 (Build 20348)
• [ ] Windows 11, version 22H2 (Build 22000)
• [ ] Other (specify)

Other SDK version

No response

Visual Studio Version

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Visual Studio Build Number

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Device form factor

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Additional context

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