Display more than 1000 options in “Select List”

Use Case

In Visual force page, a “Select List” can display up to 1000 options. If we are trying to dynamically populate a custom “Pick list” from backend Controller class

and it tries to add more than 1000 Options to custom “Pick list”, it throws exception: “Collection size 1001 exceeds maximum size of 1000”!

Solution

Solution to such scenario is, we can make the custom “Select List” as a paginated one. Which basically means, when there is less than 1000 Options returns

by query, it will behave normal way. But then the query result is more than 1000, only 1000 Options will be added to “Select List” component with “Next” and “Previous” options as applicable.

Code Snippet

Visual Force Page

<apex:page controller="PaginatedList">

                <apex:form id="pgForm">

                                <b><apex:outputLabel value="Select : "/></b>

                                <apex:selectList id="compSel" value="{!selection}" size="1">

                                                <apex:selectOptions value="{!items}"/>

                                                <apex:actionSupport event="onchange" action="{!change}" rerender="compSel,lblDis"/>                    

                                </apex:selectList>

                                <p/>

                                <b><apex:outputLabel value="Selected : "/></b>

                                <apex:outputLabel id="lblDis" value="{!selection}"/>   

                </apex:form> 

</apex:page>

Controller Class

public class PaginatedList {

       

        public List<String> lstItems = new List<String>();

       

        private String selection;

        private Integer startIndex = 0;

        private Integer endIndex = 0;

               

        private Integer ACTUAL_SIZE = 0;

        private final Integer ALLOWED_LIST_SIZE=1000;

                 

        public PaginatedList (){

            lstItems.clear();

            for(Integer n=1; n<=3001; n++){

                lstItems.add(n+'');  

            }

            ACTUAL_SIZE = lstItems.size();

            Integer tempVar = (ACTUAL_SIZE <= ALLOWED_LIST_SIZE)? ACTUAL_SIZE:ALLOWED_LIST_SIZE;

            startIndex = 0;

            if(ACTUAL_SIZE == ALLOWED_LIST_SIZE || tempVar < ALLOWED_LIST_SIZE)

                endIndex = tempVar - 1;

            else

                endIndex = tempVar - 2;   

            selection = lstItems[0];

        }

               

        public PageReference change(){

           

            if (selection == 'next'){

                startIndex = endIndex + 1;

                Integer tempVar = ((ACTUAL_SIZE - endIndex)< ALLOWED_LIST_SIZE)? (ACTUAL_SIZE - endIndex): ALLOWED_LIST_SIZE;

                if (tempVar == ALLOWED_LIST_SIZE)

                    endIndex  = endIndex  + (tempVar - 2);

                else

                    endIndex  = endIndex  + (tempVar - 1);

            }

            if (selection == 'prev'){               

                endIndex = startIndex - 1;

                if(endIndex > ALLOWED_LIST_SIZE)

                    startIndex = startIndex - (ALLOWED_LIST_SIZE - 2);

                else

                    startIndex = startIndex - (ALLOWED_LIST_SIZE - 1);      

            }   

            return null;

        }

           

        public List<SelectOption> getItems(){            

            List<SelectOption> options = new List<SelectOption>();

            if(startIndex > 0){

                options.add(new SelectOption('prev','- prev -'));               

            }                      

            for(Integer i=startIndex; i<=endIndex; i++){

                options.add(new SelectOption(lstItems[i],lstItems[i]));  

            }

            if((ACTUAL_SIZE - startIndex) > ALLOWED_LIST_SIZE){

                options.add(new SelectOption('next','- next -'));               

            }                     

            return options;

        }

         

        public String getSelection(){

            if(selection == 'next' || selection == 'prev')

                selection = lstItems[startIndex];

            return selection;

        }

           

        public void setSelection(String selection){           

            this.selection = selection;

        }

}

NOTE : Only place need to change is marked. lstItems list will be the one in your code which will be populated by required query.

Screen shots