Maui -- How to make the background color transparent?

Question

I'm trying to write a program that would be used as an overlay on top of another program. I want the text, buttons, and border to be solid, and the background to be transparent.

<VerticalStackLayout Spacing="25" Padding="30" BackgroundColor="Transparent" IsVisible="True" Opacity="1">

That works for one of the layers, but it appears that there are multiple layers.

Here it mentions changing the ContentPage, which I tried, and it appears not to be working.

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="NameSpace.MainPage"
         xmlns:local="clr-namespace:NameSpace"    
         BackgroundColor="Transparent">

I also tried:

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="NameSpace.MainPage"
         xmlns:local="clr-namespace:NameSpace.Core.Views.CustomControls"    
         BackgroundColor="Transparent">

I changed the Shell to include a Transparent background color, which didn't help.

<Shell
x:Class="NameSpace.AppShell"
xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:NameSpace"
Shell.FlyoutBehavior="Disabled"
BackgroundColor="Transparent">

It appears that nothing changed when changing either the ContentPage or the Shell.

None of those seem to change the background color behind the VerticalStackLayout. Any ideas?

Rebuttal

So you are running this on Windows (not a mobile device)? It must be something within the platform-specific code. You might have to examine the source code for Maui, then write a WindowHandler that changes the default behavior. The relevant source might be maui ..Core/src/Handlers/Window/WindowHandler.Windows.cs. To learn about Maui handlers, see Customize controls with handlers... – Stitt

... HOWEVER, I don't know whether there is anything special about WindowHandler, that requires something different. NOTE: The Xamarin link you gave refers to pages WITHIN the app; it was about overlaying two app pages within the SAME program - there was no concept in Xamarin that could allow overlaying on a DIFFERENT program. – Stitt

Yep, I'm running this on Windows. Thank you for giving me another path to look down – Rebuttal

Answer 1

I know this is old question but maybe can help another you can use hex alpha for colors.

You need to use this alpha codes with color code Alpha + Color, for example #80FFFFFF

• 100% — FF
• 99% — FC
• 98% — FA
• 97% — F7
• 96% — F5
• 95% — F2
• 94% — F0
• 93% — ED
• 92% — EB
• 91% — E8
• 90% — E6
• 89% — E3
• 88% — E0
• 87% — DE
• 86% — DB
• 85% — D9
• 84% — D6
• 83% — D4
• 82% — D1
• 81% — CF
• 80% — CC
• 79% — C9
• 78% — C7
• 77% — C4
• 76% — C2
• 75% — BF
• 74% — BD
• 73% — BA
• 72% — B8
• 71% — B5
• 70% — B3
• 69% — B0
• 68% — AD
• 67% — AB
• 66% — A8
• 65% — A6
• 64% — A3
• 63% — A1
• 62% — 9E
• 61% — 9C
• 60% — 99
• 59% — 96
• 58% — 94
• 57% — 91
• 56% — 8F
• 55% — 8C
• 54% — 8A
• 53% — 87
• 52% — 85
• 51% — 82
• 50% — 80
• 49% — 7D
• 48% — 7A
• 47% — 78
• 46% — 75
• 45% — 73
• 44% — 70
• 43% — 6E
• 42% — 6B
• 41% — 69
• 40% — 66
• 39% — 63
• 38% — 61
• 37% — 5E
• 36% — 5C
• 35% — 59
• 34% — 57
• 33% — 54
• 32% — 52
• 31% — 4F
• 30% — 4D
• 29% — 4A
• 28% — 47
• 27% — 45
• 26% — 42
• 25% — 40
• 24% — 3D
• 23% — 3B
• 22% — 38
• 21% — 36
• 20% — 33
• 19% — 30
• 18% — 2E
• 17% — 2B
• 16% — 29
• 15% — 26
• 14% — 24
• 13% — 21
• 12% — 1F
• 11% — 1C
• 10% — 1A
• 9% — 17
• 8% — 14
• 7% — 12
• 6% — 0F
• 5% — 0D
• 4% — 0A
• 3% — 08
• 2% — 05
• 1% — 03
• 0% — 00

Camion

Answer 2

Fully transparent windows aren't currently supported. MAUI runs on WinUI for Windows apps, and WinUI doesn't yet support transparent windows. There are open feature requests for it at:

• Proposal: Borderless transparent window background support in apps using WinUI #1247
• In WinUI 3, is it possible to create a transparent Xaml Island overlay on top of parent hwnd? #2956

Woodrowwoodruff