部署后返回500

When debugging I was using the debug config (Which I had generated XmlComments for: Properties -> build tab -> Output -> XML Documentation File)

I had not done this for my release configuration (duh...) - now everything works

Swashbuckle is hiding the real error message due to your customErrors setting in web.config. If you set customErrors to off you should get a better error message.

<system.web>
<customErrors mode="Off"/>
</system.web>

The issue is that running dotnet publish with -r Release does not produce XML file. However, dotnet publish with -r Debug does in fact produce the file. This explains why people are only getting this issue when they are deploying to environments OTHER than locally, then kicking themselves when the find the exception only occurs on prod.(ITS THE RELEASE) In order to reporoduce, simply run those command locally and view output directory and you should see the issue.

(UPDATE) The fix for me was to actually go into .csproj file and add a line to ensure that the file was copied over always. Diff shown below

The accepted answer should be the first thing you try.

However, I have my XML output set to go to App_Data\ and have my Swashbuckle configured to read from that directory, so, it doesn't matter which way it gets built: the xml files are going to 'be there'. Nevertheless, I was still getting the error...

I found over at MSDN's forums @enough2012's answer:

select "Remove additional files at destination" in the "File Publish Options" within the "Settings" pane of the Publish dialog.

Worked like a charm!

As stated in the accepted answer you have to make sure the XML documentation file output is in bin and not bin\Debug or bin\Release (verify this for all build configurations).

I still got the 500 response because I use multiple XML documentation files. In my SwaggerConfig implementation I include XML documentation files from two projects (the WebApi project itself and a class library that is referenced by the WebApi project):

c.IncludeXmlComments(string.Format(@"{0}\bin\MyWebApiProject.xml", System.AppDomain.CurrentDomain.BaseDirectory));
c.IncludeXmlComments(string.Format(@"{0}\bin\ReferencedProject.xml", System.AppDomain.CurrentDomain.BaseDirectory));

The XML documentation file of the WebApi project was published correctly to the bin folder of the site, however the XML documentation file of the referenced project was not (even though it appears in the bin folder of the compiled project).

So you need to modify the WebApi project file (.csproj) in a text editor and add the following sections at the bottom (replace ReferencedProject):

<PropertyGroup>
<CopyAllFilesToSingleFolderForPackageDependsOn>
CustomCollectFiles;
$(CopyAllFilesToSingleFolderForPackageDependsOn);
</CopyAllFilesToSingleFolderForPackageDependsOn>
<CopyAllFilesToSingleFolderForMsdeployDependsOn>
CustomCollectFiles;
$(CopyAllFilesToSingleFolderForMsdeployDependsOn);
</CopyAllFilesToSingleFolderForMsdeployDependsOn>
</PropertyGroup>
<Target Name="CustomCollectFiles">
<ItemGroup>
<_CustomFiles Include="..\ReferencedProject\bin\ReferencedProject.xml" />
<FilesForPackagingFromProject Include="%(_CustomFiles.Identity)">
<DestinationRelativePath>bin\%(Filename)%(Extension)</DestinationRelativePath>
</FilesForPackagingFromProject>
</ItemGroup>
</Target>

See How do you include additional files using VS2010 web deployment packages? for a full explanation.

thank you @VisualBean.

As it was not so obvious for me .... how to... a simple image.

In Project > Your Project properties > Build Tab