Visual Web Part cannot be found or is not registered as safe, and isn't being added to web.config

Question

I'm new to SharePoint development, and I'm making a basic Visual Web Part with Visual Studio 2015, which currently only displays a header. It successfully builds and deploys, however the SharePoint 2016 site returns the error:

A Web Part or Web Form Control on this Page cannot be displayed or imported. The Type <Namespace>.VisualWebPart1.VisualWebPart1, ..., PublicKeyToken=<#> could not be found or is not registered as safe.

The Properties window of the Web Part has all the correct information, and after some digging I've discovered that the web.config file doesn't update correctly. In this post, examining a similar error, the chosen answer explains that the Manifest.xml file handles the web.config updating, and I've noticed that VS hasn't (and I suspect won't) make this file for me.

Is there a fix in Visual Studio that I can correct to have it make this file for me, or do I have to make this manually? If I do have to make the Manifest manually, what does it consist of?

Answer 1

When webpart deployed successfully, there will be a SafeControl map to web part.

For example:

<SafeControl Assembly="SP2016Project, Version=1.0.0.0, Culture=neutral, PublicKeyToken=3d20aa9b415aaf50" Namespace="SP2016Project.FirstVisualWebPart" TypeName="*" Safe="True" />

If you can't find this in your web.config(C:\inetpub\wwwroot\wss\VirtualDirectories\port), you could try to register it manually.How to get assembly PublicKeyToken