No effect with 'inject' when use FileSystem Project

Same with #211 , When I use FileSystem Project (UseFilesystemProject(projectPath)), like this:

var engine = new RazorLightEngineBuilder()
    .UseFilesystemProject(projectPath)
    .UseMemoryCachingProvider()
    .Build();

services.AddRazorLight(() => engine);

and inject in tamplate like this: @inject IConfiguration configuration

Finally, I got a NullReferenceException, what should I do ? Thanks~

[smartlei24]

Hi, @toddams I find this problem, in source code of method AddRazorLight:

            services.AddSingleton<IRazorLightEngine>(p => 
            {
                var engine = engineFactoryProvider();
                AddEngineRenderCallbacks(engine, p);

                return engine;
            });

Method AddEngineRenderCallBacks be called when dotnet core injects IRazorLightEngine, but I don’t inject it and make engine as a prop to other class, and inject other class, like this:

            var render = new RazorFileSystemRenderer(templatePath);

            builder.Services.AddRazorLight(() => render._engine);
            builder.Services.AddSingleton<ITemplateRenderer>(render);
            return builder;

@Andrioden Maybe your problem is the same reason.

[jzabroski]

@smartlei24 Thanks for all your help explaining this problem.

        var render = new RazorFileSystemRenderer(templatePath);

        builder.Services.AddRazorLight(() => render._engine);
        builder.Services.AddSingleton<ITemplateRenderer>(render);
        return builder;

So, I think there may be several red flags here.

One, that I didn’t notice before, is “builder.”. I think what builder is matters a lot here. Are you by any chance using Blazor - I found this via searching code snippets for “builder.Services”

Two, why aren’t you simply doing the following:

serviceCollection.TryAddSingleton<IRazorLightTemplateRenderer, RazorLightTemplateRenderer>();
serviceCollection.AddRazorLight(() => extractedOutCallToRazorLightEngineFrom_new_RazorLightTemplateRenderer);

and

public class RazorLightTemplateRenderer : IRazorLightTemplateRenderer
{
  RazorLightTemplateRenderer(IRazorLightEngine razorLightEngine)
  {
    // todo
  }
}
}