Скачать или смотреть How to Fix App Manifest Validation Errors in Visual Studio 2019 After Update

Learn how to resolve `App Manifest Validation Errors` in Visual Studio 2019 after updating to version 16.8.0. Follow these easy steps for a seamless development experience.
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Resolving App Manifest Validation Errors After Upgrading Visual Studio 2019

When you're developing an application using Universal Windows Platform (UWP) and you update your Visual Studio to the latest version, the last thing you want to encounter is an app manifest validation error. This issue can be quite frustrating, especially if everything was working perfectly before the update. In this guide, we'll explore this issue, what causes it, and how to effectively resolve it.

The Problem: App Manifest Validation Error

After updating to Visual Studio 2019 16.8.0, users have reported encountering the following error when building their project:

[[See Video to Reveal this Text or Code Snippet]]

This error typically arises due to duplicate entries in the app's manifest file that are incompatible with the new version of Visual Studio.

Key Observations:

The error specifically indicates that the LottieVisualSource is being declared multiple times in your AppxManifest.xml file.

The build process works perfectly on an older version (like 16.7.7) but fails after an update.

Diagnosis: Understanding the Manifest Changes

Based on the observations, it's essential to compare the app manifest generated in both Visual Studio versions to identify the issue.

Manifest Comparison

Manifest in VS 16.7.7:

[[See Video to Reveal this Text or Code Snippet]]

Manifest in VS 16.8.0:

[[See Video to Reveal this Text or Code Snippet]]

Identifying the Cause

The duplication occurs due to the automatic addition of CLRHost.dll, leading to the same activatable class ID being declared multiple times. This change is likely a consequence of modifications in how Visual Studio handles configurations in this release.

The Solution: Resolving the Issue

Fortunately, there's a straightforward solution available for this error.

Steps to Resolve the Manifest Validation Error:

Backup Your Project: Always start with a backup to avoid losing any progress.

Clean the Solution: Go to the "Build" menu and select "Clean Solution" to remove out any previous build data.

Rebuild the Project: Try rebuilding your project to see if the problem persists.

Delete and Clone Again:

Delete the local project folder.

Clone the project again from your remote repository. This action ensures you have a fresh copy of the project without corrupted settings or files.

Edit AppxManifest.xml (If Needed):

If the issue still persists, manually edit your AppxManifest.xml to ensure there are no duplicate entries.

Note:

It's important to remember that re-cloning is a temporary solution. For a permanent fix, you should monitor updates from Microsoft regarding this issue in future releases.

Conclusion

Manifest validation errors can be a common pitfall after updates in development environments like Visual Studio 2019. By understanding the source of the problem and following the solution steps outlined above, you can resolve these validation issues and get back to building your apps.

If you find any better solutions or reasoning behind the discrepancies, feel free to share it with the community! Happy coding!