VF page show last record instead of selected one

Question

I have standard object tab and added object button to VisualForce page on it. The VF have very simple code:

    <apex:page standardController="Contract" recordSetVar="Contract">
     <apex:pageBlock title="The id of the Contract Standard object">
        <apex:pageBlockTable value="{!Contract}" var="a">
            <apex:column value="{!a.Status}"/>
            <apex:column value="{!a.ContractNumber}"/>
        </apex:pageBlockTable>
    </apex:pageBlock>  
</apex:page>

But when i click the button the VF page display always the last record instead of selected one:

Is there a way to make the VF page display selected record (or records, could be more than one selected) instead of last one?

Answer 1

StandardSetControllers maintain two lists of records, one of which is the set of selected records, and this information can come from a list view as you desire.

Swapping out the name of your recordSetVar in the page block table for {!selected} (which calls the Apex method getSelected() from the StandardSetController class in the background) should do the trick:

   <apex:pageBlockTable value="{!selected}" var="a">
       <apex:column value="{!a.Status}"/>
       <apex:column value="{!a.ContractNumber}"/>
   </apex:pageBlockTable>