Issue with .NET MAUI Microsoft.Maui.Controls 9.0 Update. Error (CS0246)

[tecomunico]

Description

Hi everyone,

I am experiencing an issue after updating Microsoft.Extensions.Logging.Debug, Microsoft.Maui.Controls, Microsoft.Maui.Controls.Compatibility, etc., from version 8.0.93 to 9.0. The error specifically appears in the AppDelegate class for iOS. The line causing the problem is:

public class AppDelegate : MauiUIApplicationDelegate

The error message I am receiving is:

Platforms/iOS/AppDelegate.cs(28,28): Error CS0246: The type or namespace name 'MauiUIApplicationDelegate' could not be found (are you missing a using directive or an assembly reference?) (CS0246)

I have tried troubleshooting this issue on different machines, but the problem persists across all of them. I even created a completely new MAUI project, and the error still appears immediately after updating to version 9.0. It seems like the update is causing this problem, and I cannot proceed with iOS builds because of it.

Has anyone found a solution or workaround for this? Any help would be greatly appreciated, as this is really blocking our progress.

Thanks in advance!

Steps to Reproduce

No response

Link to public reproduction project repository

No response

Version with bug

9.0.0 GA

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.100 SR10

Affected platforms

iOS

Affected platform versions

iOS 15 Pro Max 17.0 Visual Studio for Mac 17.6.14 (build 413)

Did you find any workaround?

No response

Relevant log output

[similar-issues-ai]

We've found some similar issues:

• The type or namespace name 'MauiUIApplicationDelegate' could not be found Microsoft.AspNetCore.Components.WebView.Maui 8.0.7 #20591 , similarity score: 83%
• MauiUIApplicationDelegate could not be found #24009 , similarity score: 83%
• Error CS0246: The type or namespace name 'MauiUIApplicationDelegate' could not be found (are you missing a using directive or an assembly reference?) #20638 , similarity score: 83%
• Another - Error CS0246: The type or namespace name 'MauiUIApplicationDelegate' could not be found (are you missing a using directive or an assembly reference?) (CS0246) #21751 , similarity score: 81%
• Error CS0246: The type or namespace name 'MauiUIApplicationDelegate' could not be found (are you missing a using directive or an assembly reference?) (CS0246) #20649 , similarity score: 81%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[Zhanglirong-Winnie]

Hi, @tecomunico
Microsoft.Maui.Controls and Microsoft.Maui.Controls.Compatibility rely on the .NET 9 SDK. You need to install the .NET 9 SDK and the corresponding .NET 9 MAUI Workload on your machine.
Download .NET 9.0 (Linux, macOS, and Windows) (microsoft.com).
Please try to see if this solves your problem and give us feedback. We look forward to your reply.

[Barry-Theunissen]

It does NOT solve the problem. TEST TEST TEST Microsoft, before you release something!! FFS...again and again and again this sort of sh_t happens! Microsoft.Maui.Controls NuGet upgrade to 9.0.10 is a complete waste of time of a release right now - doesn't work - was not tested properly...only solution is to go back to 8.0.100!!!