Error adding settings page in WinUI 3 MVVM app using Template Studio

TUAN THANH VO 0

I'm trying to add a settings page to my existing WinUI 3 app using Template Studio (With Navigation Bar) with the MVVM pattern. However, I'm encountering the following error:

System.Exception: Error executing 'Microsoft.Templates.Core.PostActions.Catalog.Merge.MergePostAction'. Related template: ts.WinUI.MVVMToolkit.Feat.ThemeSelection. ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at Microsoft.Templates.Core.PostActions.Catalog.Merge.MergeHandler.FindAndModifyContextLine(String mergeLine, Int32 diffTrivia)
   at Microsoft.Templates.Core.PostActions.Catalog.Merge.MergeHandler.Merge(IEnumerable`1 source, IEnumerable`1 merge)
   at Microsoft.Templates.Core.PostActions.Catalog.Merge.MergePostAction.ExecuteInternal()
   at Microsoft.Templates.Core.PostActions.PostAction.Execute()
   --- End of inner exception stack trace ---
   at Microsoft.Templates.Core.PostActions.PostAction.Execute()
   at Microsoft.Templates.Core.Gen.GenController.ExecutePostActions(GenInfo genInfo, ITemplateCreationResult generationResult)
   at Microsoft.Templates.Core.Gen.GenController.<GenerateItemsAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Templates.Core.Gen.NewItemGenController.<UnsafeGenerateNewItemAsync>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Templates.UI.Services.GenerationService.<GenerateNewItemAsync>d__6.MoveNext()

This is the problem i faced
User's image

I've tried the following steps:

Ensured that I'm using the latest version of Template Studio.

Checked the App.xaml.cs and theme-related files for any discrepancies.

However, the issue persists. Could someone please help me resolve this error?

Junjie Zhu - MSFT 19,321 Reputation points Microsoft Vendor

2024-11-25T06:58:47.5333333+00:00

Hello @TUAN THANH VO ,

Welcome to Microsoft Q&A!

Your screenshot seems to be different from my Template Studio for WinUI (C#). Which extension are you using?

Please make sure that the environment required by WinUI3 project, especially Windows.APP.SDK is correctly installed.

Thank you.
TUAN THANH VO 0 Reputation points

2024-11-25T07:17:34.6233333+00:00

@Junjie Zhu - MSFT
Thank you for answering my question.

As I mentioned, I am adding a Settings Page to an existing WinUI3 application through Template Studio, not during the initial setup with Template Studio. When I create a new application, it works the same as yours. However, since I didn’t add the Settings Page at the time of creation, I am now unable to add it due to the aforementioned error. That said, I can still add a blank page. I think this issue occurs because Template Studio cannot merge my existing code with the code generated when creating the Settings Page.
Junjie Zhu - MSFT 19,321 Reputation points Microsoft Vendor

2024-11-25T07:34:18.7233333+00:00

Hello @TUAN THANH VO ,

I got it, I tried it and successfully added a new Settings page. I suggest you reinstall the extension or Visual studio. If it still doesn't work, I suggest you submit this issue on https://github.com/microsoft/TemplateStudio/issues.

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Error adding settings page in WinUI 3 MVVM app using Template Studio

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