[Windows] fixing window glitches while moving or resizing

[salarcode]

Description of Change

IWindow.FrameChanged is a hot path and is being called many times while a window is moved or resized.
The number of calls sky rockets when dpi is being changed as the window is being moved to a different monitor with different scalling.
While the method tries to update IWindow bindable properties it causes a chain of updates that cycles back to itself and then updates the window again.

This fix tries to prevent this cycle and delay/separate the bindable property updates.

As result

• The bug is fixed
• The app window is a little more responsive when resizing/moving

Before the change:

Maui.Controls.Sample_Xl8BmnifAD.mp4

MAUI.Windows.MultiDpi.monitor.mp4

---

After the fix

After.fix.mp4

Issues Fixed

Fixes (but reverted) #11777
Fixes (but reverted) #14597 (dupe)

[ghost]

Hey there @salarcode! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[salarcode]

@dotnet-policy-service agree

[mattleibow]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[mattleibow]

I wonder if this should actually make use of the new feature @hartez added with update direction. So when it is coming from the platform, we don't actually go back into the platform.

I think this is currently used on Android for entry text. It would go into this same cycle.

[salarcode]

I'm not sure if there is anything I need to do here?

[salarcode]

FYI this also affects Blazor Hybrid with .NET MAUI apps
And is a regression from .NET 6

[mattleibow]

I am not 100% sure that splitting up the bindable property is the correct action.

We do have a new way to track where the update comes from and we could use that instead.

@PureWeen do you have any thoughts?

[hartez]

I am not 100% sure that splitting up the bindable property is the correct action.

We do have a new way to track where the update comes from and we could use that instead.

We have DataFlowDirection, but that isn't really fully-baked yet; it was just the only option we had at the time. (That's why it's still marked as internal.) It would work for this situation, but it would be a little awkward because you'd have to force a cast to ViewHandler to set it. And we haven't really settled on that mechanism as a permanent solution.

My worry about the solution in this PR is that I think if you have anything with a data binding to one of the Window's frame properties, the value won't update. For example, if I bind a Label's Text property to the X property of the Window, does SetValuePrivateFlags.Silent keep the binding from updating?

[mattleibow]

@StephaneDelcroix are there thoughts?

[salarcode]

I am not 100% sure that splitting up the bindable property is the correct action.

I would prefer to have some kind of batch update as core functionality for bindable properties, something like this:

SetValueBatch((XProperty, x), (YProperty, y), (WidthProperty, width), (WidthProperty, width), (HeightProperty, height));


void SetValueBatch(params (BindableProperty property, object value)[] props)
{
	SetPropertyChanging(...);
	...
	SetValueCore(...);
	...
	SetPropertyChanged(...);
}

but this PR is a fix with what we have.

[salarcode]

My worry about the solution in this PR is that I think if you have anything with a data binding to one of the Window's frame properties, the value won't update. For example, if I bind a Label's Text property to the X property of the Window, does SetValuePrivateFlags.Silent keep the binding from updating?

That is taken care of here and it works fine as it can be tested in this sample:

maui/src/Controls/samples/Controls.Sample/Pages/Core/MultiWindowPage.xaml

Lines 18 to 22 in dec8b24

	<Label Text="Current Window Frame:" />
	<Label Text="{Binding Window.X, StringFormat='X = {0:0.00}'}" />
	<Label Text="{Binding Window.Y, StringFormat='Y = {0:0.00}'}" />
	<Label Text="{Binding Window.Width, StringFormat='W = {0:0.00}'}" />
	<Label Text="{Binding Window.Height, StringFormat='H = {0:0.00}'}" />

[hartez]

My worry about the solution in this PR is that I think if you have anything with a data binding to one of the Window's frame properties, the value won't update. For example, if I bind a Label's Text property to the X property of the Window, does SetValuePrivateFlags.Silent keep the binding from updating?

That is taken care of here and it works fine as it can be tested in this sample:

maui/src/Controls/samples/Controls.Sample/Pages/Core/MultiWindowPage.xaml

Lines 18 to 22 in dec8b24

	<Label Text="Current Window Frame:" />
	<Label Text="{Binding Window.X, StringFormat='X = {0:0.00}'}" />
	<Label Text="{Binding Window.Y, StringFormat='Y = {0:0.00}'}" />
	<Label Text="{Binding Window.Width, StringFormat='W = {0:0.00}'}" />
	<Label Text="{Binding Window.Height, StringFormat='H = {0:0.00}'}" />

Then I don't have any objections to this.

[salarcode]

Any update on this?

[mattleibow]

I would like a review from @StephaneDelcroix just in case there is some side effect of doing this, especially in the light of the other changes he is doing.

[StephaneDelcroix]

looks fine, might need to be reviewed when my specificity PR is merged

[salarcode]

Any luck getting this in?

[mattleibow]

No idea how I missed the review from Stephane... Sorry about that.

@salarcode If you rebase so we can make sure all the new tests stick, I'll merge. If I rebase than I can't merge.

[salarcode]

No idea how I missed the review from Stephane... Sorry about that.

@salarcode If you rebase so we can make sure all the new tests stick, I'll merge. If I rebase than I can't merge.

No problem. It is done

[mattleibow]

/azp run

[azure-pipelines]

No commit pushedDate could be found for PR 14861 in repo dotnet/maui

[rmarinho]

/azp run

[azure-pipelines]

No commit pushedDate could be found for PR 14861 in repo dotnet/maui

[rmarinho]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[lfmouradasilva]

Any forecast for this to be released? I have a problem in production

[danielancines]

Hi there, any idea when this fix is going to be released on .NET 7?
We are building a big software using .NET Maui and the app is crashing sometimes because of this error.

[lfmouradasilva]

Any workarounds?

[danielancines]

Morning guys, I placed this code on my windows applications and it worked like a charm. Thank you, I hope this fix comes to official release soon.

[rmarinho]

Seems iOS is failing with a StackOverflow exception and I wonder if it's from the Window changes.

[salarcode]

I don't have an iOS device to test this, not sure why test is failing there, it was successful before! Maybe it`s something unrelated?

[salarcode]

This fix does not work anymore after the commit 83398c38d0356c89e62c184ff088a992bb86c7d0 because the method SetValueCore does not respect SetValuePrivateFlags.Silent which it used to do