<apex:page standardController="Campaign" extensions="ForSaleLookupOnCampaignController"> 
    <script type="text/javascript">
        function selectAllCheckboxes(obj,receivedInputID){
            var inputCheckBox = document.getElementsByTagName("input");                  
            for(var i=0; i<inputCheckBox.length; i++){          
                if(inputCheckBox[i].id.indexOf(receivedInputID)!=-1){                                     
                    inputCheckBox[i].checked = obj.checked;
                }
            }
        }
   
}
    </script>
    <apex:form >
        <apex:pageBlock >
             <apex:pageBlockButtons >
                <apex:commandButton value="Save" style="width: 100px; height: 30px" action="{!processSelected}" rerender="table2"/>
            </apex:pageBlockButtons>
            <p style="font-size: 15px;font-weight: bold;">Select FID :</p><apex:inputfield style="width: 200px; height: 30px" value="{!Campaign.For_Sale__c}" id="forsaleid"/><br/>
            <apex:pageblockSection title="Related Campaign Members" collapsible="false">
                <apex:pageBlockTable value="{!wrapcontactList}" var="conWrap" id="table" title="All Related Campaign Members">     
                    <apex:column >
                        <!--apex:facet name="header">
                          <apex:inputCheckbox onclick="selectAllCheckboxes(this,'inputId')"/>
                         </apex:facet-->
                        <apex:inputCheckbox value="{!conWrap.selected}" id="inputId"/>
                    </apex:column>
                    <apex:column value="{!conWrap.con.Name}" />
                    <apex:column value="{!conWrap.con.Account.name}" />
                </apex:pageBlockTable>
            </apex:pageblockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>

public class ForSaleLookupOnCampaignController { 
    public List<CampaignMember> Campaignmemberlist{get;set;} 
    public Campaign cmp {get;set;} 
    public List<wrapContact> wrapcontactList {get; set;}
    public List<Contact> selectedcontacts{get;set;}
    set<id>conid=new set<ID>();
    public String ID { get; set;}
    set<id>ForSaleid=new set<id>();
    public ForSaleLookupOnCampaignController (ApexPages.StandardController standardControllerParam) {
        this.cmp = (Campaign)standardControllerParam.getRecord();
        Campaignmemberlist = [SELECT id,name,Campaignid,Company__c,type,For_Sale__c,Contact.For_Sale__c  FROM CampaignMember WHERE Campaignid = : ApexPages.currentPage().getParameters().get('id') ];
        for(CampaignMember cm:Campaignmemberlist){
            conid.add(cm.ContactId);
            ForSaleid.add(cm.For_Sale__c);
        }
        //
        if(wrapContactList == null) {
            wrapContactList = new List<wrapContact>();
            for(Contact c: [select Id,Name,Account.name,For_Sale__c from Contact where id=:conid]) {
                wrapContactList.add(new wrapContact(c));
            }
        }
        
    }
    public PageReference processSelected() {
        PageReference pr;
        selectedcontacts = new List<contact>();
        system.debug('for sale '+cmp.For_Sale__c);
        for(wrapContact wrapcontactObj : wrapcontactList) {
            if(wrapcontactObj.selected == true) {
                selectedcontacts.add(wrapcontactObj.con);
                
            }
        }
        for(contact s:selectedcontacts){
            s.For_Sale__c=cmp.For_Sale__c;
        }
            try{
                
                database.update(selectedcontacts);
                
            }catch( Exception e ){
                ApexPages.addMessages(e);
            }
            system.debug('selectedcontacts'+selectedcontacts);
            ApexPages.addmessage(new ApexPages.message(ApexPages.severity.CONFIRM,'FID Update on Contact'));
      return pr;   
    }
    public class wrapContact {
        public Contact con {get; set;}
        public string forsaleid{get;set;}
        public Boolean selected {get; set;}
        
        public wrapContact(Contact c) {
            con = c;
            forsaleid=c.For_Sale__c;
            selected = false;
        }
    }
}