Page preview works fine while page rendering fails

Question

My preview works fine through Tridion UI and also through template builder.

When I publish the page I get the following error.

JScriptException: Expression 'RenderComponentPresentation()' had error 'Object reference not set to an instance of an object.'

I have this statement in my TBB.

 Tridion.ContentManager.Publishing.Rendering.Binary b = engine.PublishingContext.RenderedItem.AddBinary(file, "image.png", strGroup, name, "image/png");

I also do not get any error logs in Tridion events. But I have a warning like this.This warning ocurs as well in other environment also but still publish is success.

AddBinary was called with relatedComponent=null resulting in unmanaged binaries in Content Delivery. Please specify a related Component to prevent issues with (un)deploying binaries.

The same page is also getting published in another Tridion environment.

Can you suggest any reason for this.

Answer 1

There are (at least) three reasons why preview might succeed while publishing fails:

• Your (c#) template code may use the RenderInstruction.RenderMode property to take a different action for preview and publish

• Code which depends on assemblies in the GAC may fail if this assembly is only present on the CME server, not on the publisher server (this can only happen if you use a separate publisher machine)

• The template code may fail in publishing if you made a change to an assembly (for instance one in the GAC) on the server very recently and haven't restarted the publisher service.

I hope this gives you some idea of where to look for a solution.