Render @object and locals vs render :partial

问题:

I want to pass a local variable that contains the origin to come on a specific page, this variable contains just a symbol with the value.

When I use this code it works perfect, the origin variable is accessible in the partial :

render :partial => "products", :collection => @products, :locals => {:origin => :gallery}

But when I use this code, the origin is not set and not accessible in the partial :

render @products, :locals => {:origin => :gallery}

What is the difference here? Is the second line of code not render the partial like the first line?

回答1:

<%= render @products %>

Is indeed the shorthand syntax for rendering a partial. But with the shorthand syntax, Rails will ignore the ":locals" variable. There's more on this in the Rails Guides.

So if you want to pass extra options to the render, you have to specify ":partial => ...". If you want to know why this happens, you can take a look at the Rails source.

回答2:

There's a good explanation here: Rails: confused about syntax for passing locals to partials

The short version is that you can just omit :locals in the second example:

render @products, :origin => :gallery