Rendered doesn't work - salesforce

Question

If I try to rendered the code below it doesn't work.
If I show me the size of the list I will get the value 1, but nothing is happen.
Where is the mistake?
I tried it also with != NULL .isempty etc., the same problem.
<apex:pageblock title="Unternehmen Detail" id="pbAccDL" rendered="{!If(AccDList2.size > 0,true,false)}>
<apex:pageblocktable value="{!AccDList2}" var="AccD" rendered="{!IF(AccDList2.size != 0, true, false)">
<apex:column style="font-size:16pt; font-weight: bold" headerValue="" value="{!AccD.Name}"/>
</apex:pageblocktable>
<apex:pageblocktable value="{!AccDList2}" var="AccD" columnswidth="50%, 25%, 25%">
<apex:column value="{!AccD.BillingStreet}"/>
<apex:column value="{!AccD.BillingPostalCode}"/>
<apex:column value="{!AccD.BillingCity}"/>
</apex:pageblocktable>
Public List <Account> getAccDList2() {
List <Account> AccD = [SELECT Id, Name, RecordTypeId, Status__c, Kunde_seit__c, Billingstreet, BillingPostalCode, BillingCity FROM Account WHERE Id = :SelectedAccountId];
RETURN AccD;
}
Public pageReference getAccDList() {
getAccDList2();
//RETURN NULL;
RETURN ApexPages.CurrentPage();
}
I don't understand the problem, because I use the same function for an other pageblock and works fine.
<apex:pageblock title="Account" id="pbAcc" rendered="{!IF(AccList2.size != NULL,true,false)}">
<apex:pageblockButtons location="top">
<apex:commandButton value="page 1" rerender="pbAcc" action="{!FirstPage}" disabled="{!prev}"/>
<apex:commandButton value="prev page" rerender="pbAcc" action="{!previous}" disabled="{!prev}"/>
<apex:commandButton value="next page" rerender="pbAcc" action="{!next}" disabled="{!nxt}"/>
<apex:commandButton value="last page" rerender="pbAcc" action="{!LastPage}" disabled="{!nxt}"/>
</apex:pageblockButtons>
<apex:pageblocktable value="{!AccList2}" var="Acc" columnswidth="5%, 70%, 25%">
<apex:column headervalue="LINK">
<apex:outputLink target="_blank" value="/{!Acc.Id}">Details</apex:outputLink>
</apex:column>
<apex:column headervalue="Account">
<apex:outputField value="{!Acc.Name}" />
<apex:actionSupport event="onclick" action="{!getOppList}" rerender="pbOpp, pbAccDL, pbAccDR, pbOppD">
<apex:param assignTo="{!SelectedAccountId}" value="{!Acc.Id}" name="SelectedAccountId"/>
</apex:actionSupport>
</apex:column>
<apex:column headervalue="City">
<apex:outputField value="{!Acc.BillingCity}"/>
</apex:column>
</apex:pageblocktable>
Could someone help me please.
Thanks,
peX

Answer 1

Note that if the outer container (apex:pageBlock in your case) wasn't rendered at page load time you wouldn't be able to rerender inner elements later. To make sure this is not the problem remove rendered attribute from outer apex:pageblock. One more thing to note in your second example you are writing AccList2.size != NULL which is never the case (if AccList2 is a list) you should check with AccList2.size > 0