RazorLightException: Cant load metadata... PreserveCompilationContext

[dapug]

I'm getting the exception mentioned here:
https://github.com/toddams/RazorLight/issues/44

RazorLight.RazorLightException: Can't load metadata reference from the entry assembly. Make sure PreserveCompilationContext is set to true in *.csproj file

But I opened this because none of the suggestions resolved it. Clean/Rebuild wont fix, and adding <PreserveCompilationContext>true</PreserveCompilationContext> wont fix. I am using a Core 2.0 Unit Test app, but that shouldn't be any different than a simple console app.

[GoodGoodJM]

Where did you add <PreserveCompilationContext>true</PreserveCompilationContext>?
Try putting it in "PropertyGroup".

Like this

  <PropertyGroup>
    ...
    <PreserveCompilationContext>true</PreserveCompilationContext>
    ...
  </PropertyGroup>

I looked at the code in README and put it in ItemGroup, but it was not resolved.

I put it in PropertyGroup and I found it works.

[toddams]

Did it solve the issue? Waiting for feedback

[dapug]

Interesting. Yes that did fix it. Mine was in a PropertyGroup to begin with, but appended below other items listed in that group. I pulled it out into it's own PropertyGroup tag and it works. Cool, thanks.

So is this a hack that will always be necessary, or is there some more official fix that can be made so as not to require this manual edit?

[toddams]

You have to always set "PreserveCompilationContext". It was a mistake in documentation that it must be located in ItemGroup, and it's fixed now (thanks for the PR :)) Answering your question, it's not a hack but a requirement, as without this option RazorLight would not be able to compile your templates at runtime

[ghost]

I am trying to do this in an MSTest project for some light integration testing. As instructed, I put the PreserveCompilationContext element (with it set to true) in a property group tag (I used the existing property group tag at the top of the csproj file), however; it still gives me the error. I have run into issues similar to this in the past with unit tests. Is this something that does not work inside a unit test project and if you want to integration test compiling a razor file, you would need to test it in a console app like in the samples?

update: Just a quick sanity check for myself to ensure my code calling into RazorLight is set up properly and works as expected...

I tried pulling my DLL into a console application to confirm that it is working, (it works in the console app), this appears to be an issue with trying to run this in a unit test project.

[dapug]

Read my post above. You need to put it in its own isolated PropertyGroup. My unit test then worked fine.

[AlexTeixeira]

I have the same issue as @b1tburn3r.
I add PreserveCompilationContext to true in an isolated PropertyGroup ( at the end of the file ), but my test in failing with the error :

Can't load metadata reference from the entry assembly

Can you provide a sample of working code with UnitTest ?

[awernick]

@AlexTeixeira @b1tburn3r I was able to get it to work by cleaning the project and rebuilding.

So the following worked

dotnet clean
dotnet test

[cetintas41]

1. Go to project's folder location
2. Write ".csproj" then search
3. Find related csproj file and open it via text editor
4. Find <PropertyGroup> node.
5. Add <PreserveCompilationContext>true</PreserveCompilationContext> inside it.
6. Rebuild the solution.

[xxeasterxx]

i did the suggestions in this thread but it's still happening on net core 3.1. Any idea?

[billrob]

@xxeasterxx I just found this thread and it worked for me for a worker service.exe. Be sure you put the PropertyGroup in the csproj of your executable.

[jzabroski]

@billrob an .exe is not a .net core executable, though. @xxeasterxx issue is with netcoreapp3.1 target framework moniker.

@xxeasterxx Sorry I missed your response, but it's generally a good idea to open a new issue rather than reply to a closed one if you're stuck. You can leave a comment here and link back to the new issue to form breadcrumbs for others to follow as a courtesy. Additionally, "it's still happening" needs more information. Thank you!

[billrob]

@jzabroski My intentions was to ensure it wasn't on an underlying project and added to the project that contains the entry point to the application. I had made that mistake previously.

[jzabroski]

@billrob Great point. I had a coworker even who did that incorrectly.

[raxuser100]

I am using LinqPad which references ClassLib which in turn executes the RazorLight engine. I run into the same error:

RazorLight.RazorLightException: Can't load metadata reference from the entry assembly. Make sure PreserveCompilationContext is set to true in *.csproj file

I tried adding <PreserveCompilationContext> into the classlib csproj, though I know it will not work as it's not the entry point. LinqPad is the entry point!

Is there any way of getting around this error?

[jzabroski]

@raxuser100 From your description, you're using RazorLight.Unofficial, which isn't supported by this repository and may be quite old. nuget.org says that package was last updated last updated 6/30/2018 . Probably time for you to re-think your dependency.

[raxuser100]

You are right, thanks for pointing out version issue. Would this be the correct latest version to try:

or back in 2017 I note the official release:

Both throw the same error in LinqPad.

I've raised a StockOverflow question
https://stackoverflow.com/questions/67303505/linqpad-razorlight-executing-from-linqpad-throws-razorlight-razorlightexcepti

Thanks for your help,

Rakesh

---

From: John Zabroski @.>
Sent: 28 April 2021 16:33
To: toddams/RazorLight *@.>
Cc: raxuser100 @.>; Mention @.*>
Subject: Re: [toddams/RazorLight] RazorLightException: Cant load metadata... PreserveCompilationContext (#127)

@raxuser100https://github.com/raxuser100 From your description, you're using RazorLight.Unofficial, which isn't supported by this repository and may be quite old. nuget.org says that package was last updated last updated 6/30/2018 . Probably time for you to re-think your dependency.

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[jzabroski]

Please try the beta. I was hoping to do an official version soon but I got delayed by getting the covid-19.

[raxuser100]

So sorry to hear about your challenges with Covid... I do hope you are well and recovered now.

Thanks, I tried the version and it's still throwing the error.

Is there some way of utilising MetadataReference to solve this problem? Perhaps a long shot!

---

From: John Zabroski @.>
Sent: 28 April 2021 17:31
To: toddams/RazorLight *@.>
Cc: raxuser100 @.>; Mention @.*>
Subject: Re: [toddams/RazorLight] RazorLightException: Cant load metadata... PreserveCompilationContext (#127)

Please try the beta. I was hoping to do an official version soon but I got delayed by getting the covid-19.

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