Grails g：if = null不起作用

Question

I've been trying to put some if logic into my grails _form.gsp. Basically I want it to add an extra line to a table if model I'm passing in is null, but its not working!

I have this: -

<g:if test="${results = null}">
    banana
</g:if>

And it does nothing. I tried: -

<g:if test="${results.isEmpty()}">

But that causes the page to error on load with the message: -

Cannot invoke method isEmpty() on null object

If I try the reverse logic with <g:if test="${results != null}"> this works absolutely fine in scenarios where I know the model being passed in isn't empty! What am I missing?

Answer 1

you need a double "==" for your if statement:

<g:if test="${results == null}">
                       ^
                       |

Answer 2

Since its Grails..

<g:if test="${ !results }">

would also work.. Just a shorter version