Getting "'Icon' is obsolete" warning on build

Hi,

Since I've updated to the version 2.9.0 version, I'm having the following warning when building:

warning CS0612: 'Icon' is obsolete

I've try changing the calls to Window.SetIcon for Window.SetTitleBarIcon but I get the same result.

I've not seem any release notes regarding this. Is there something I can do to fix that?

Thank you!

The icon class in WinUI has issues with high-resolution icons, and have since been replaced by Microsoft's own icon methods. You can use the Window's icon methods: ie MyWindow.AppWindow.SetTitleBarIcon(...), MyWindow.AppWindow.SetIcon(...) and MyWindow.AppWindow.SetTitleBarIcon(...)

WinUIEx will generally deprecate features as the WinAppSDK offers new SDKs with the same features.

I'll look into updating the obsolete warning to make this more clear.

Um... I seem to already be calling SetIcon on the AppWindow. Did I understood you correctly? 😄

You wrote Window.SetIcon, not AppWindow.SetIcon. The one on AppWindow is part of the WinAppSDK and not part of WinUIEx and shouldn't give you an obsolete warning.

I'm getting the same warnings coming from TaskBarIcon in XamlTypeInfo.g.cs when I use WindowEx, even though I am not setting it (I can do global replace for WindowEx to Window and the only change is these warnings).

I am not getting any warnings for SystemBackdrop despite it also being marked obsolete, and the only difference seems to be whether the Obsolete attribute has a description, and whether there is an EditorBrowsable(EditorBrowsableState.Never) attribute.

1>D:\Source\Experiments\obj\x86\Debug\net9.0-windows10.0.26100.0\XamlTypeInfo.g.cs(308,36,308,56): warning CS0612: 'Icon' is obsolete
1>D:\Source\Experiments\obj\x86\Debug\net9.0-windows10.0.26100.0\XamlTypeInfo.g.cs(422,134,422,154): warning CS0612: 'Icon' is obsolete
1>D:\Source\Experiments\obj\x86\Debug\net9.0-windows10.0.26100.0\XamlTypeInfo.g.cs(576,51,576,71): warning CS0612: 'Icon' is obsolete
1>D:\Source\Experiments\obj\x86\Debug\net9.0-windows10.0.26100.0\XamlTypeInfo.g.cs(1153,33,1153,53): warning CS0612: 'Icon' is obsolete

You wrote Window.SetIcon, not AppWindow.SetIcon. The one on AppWindow is part of the WinAppSDK and not part of WinUIEx and shouldn't give you an obsolete warning.

Yes sorry, I mistyped. In my MainWindow, which is a WindowEx, I am calling AppWindow.SetIcon.

I am seeing the same thing, despite not using the Icon class or calling SetIcon anywhere in my WinUI app.

\obj\x64\Debug\net9.0-windows10.0.26100.0\win-x64\XamlTypeInfo.g.cs(1070,38,1070,58): error CS0612: 'Icon' is obsolete

#pragma warning disable 0618  //   Warning on Deprecated usage
            _typeTable[362] = typeof(global::WinUIEx.Icon);
#pragma warning restore 0618

Address most compiler warnings from generated code reported in #247

@duckblaster

Thank you. Especially @duckblaster : Your comment lead to the solution for most of the warnings just by adding a missing description on the obsolete attribute. An obsolete attribute without a description generates warning CS0612 which WinAppSDK doesn't suppress., but it will suppress CS0618 which is generated if you do have a description.
Unfortunately there appears to be a bug in the code generator for one of the warnings which it forgot to suppress - I'll log a bug in the WinUI repo for that: microsoft/microsoft-ui-xaml#10855

If you have an .editorconfig file, you can add the following to suppress it for now:

# Workaround for https://github.com/microsoft/microsoft-ui-xaml/issues/10855
[XamlTypeInfo.g.cs]
dotnet_diagnostic.CS0612.severity = none
dotnet_diagnostic.CS0618.severity = none

Going to close this for now, since I've addressed what I can, logged an issue in the WinUI repo with a proposed fix for the last warning, and provided a workaround above.

Would it make sense to release a 2.9.1 including 7c10504?

@mfeingol

@mfeingol probably :-) However it won't fix them all because of the Microsoft bug. Can you use the workaround for now?

Suppress diagnostics CS0612 and CS0618

This is now fixed in Windows App SDK 2.6.4: https://learn.microsoft.com/en-us/windows/apps/windows-app-sdk/release-notes/windows-app-sdk-2-0?pivots=stable#version-264
PR: microsoft/microsoft-ui-xaml#11738

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Getting "'Icon' is obsolete" warning on build #247

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Getting "'Icon' is obsolete" warning on build #247

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dotMorten commented on Oct 23, 2025

Jak3b0 commented on Oct 23, 2025

dotMorten commented on Oct 23, 2025

duckblaster commented on Oct 24, 2025

Jak3b0 commented on Oct 24, 2025

mfeingol commented on Oct 24, 2025

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mfeingol commented on Nov 13, 2025

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