How to use rendercondition visualforce on map

Question

I have a map from which i get the value in visualforce. How do I use the redner condition to check that if the falue is empty it will not render. I get the error:

Incorrect parameter type for function 'not()'. Expected Boolean, received Object

See my visualforce:

  <apex:outputtext rendered="{!IF(!candidateFieldMap != null,true, false)}">
                    <span class="header">motivation</span><br />
                         <cxsrec:getMapValue map="{!candidateFieldMap.PersonalMotivation__c}" key="PersonalMotivation__c" /><br /> 
                    </apex:outputText>

Answer 1

Try ISNULL() or ISBLANK() and use capital letters for NOT()

rendered="{!NOT(ISNULL(candidateFieldMap))}"

Or avoid NOT() altogether:

rendered="{!IF(ISNULL(candidateFieldMap),false,true)}"

Answer 2

Try this:

Create a Boolean property in Apex class to check if the map is empty, and use that for rendered tag:

public boolean getIsCandidateMapEmpty() {
    return candidateFieldMap.size() == 0;
}

Then, in vf page:

rendered="{!NOT(IsCandidateMapEmpty)}"

reference: https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/pages_variables_functions.htm