SalesForce: Searching with Multipicklist Available Values

         I have to crate a custom search form which has a drop-down having a multi-pick list available values as options. The search is to find some child records based on any one of the selected value of a multi-pick list . So I have crated a pick list (drop-down) with options as the available values of the multi-pick list . For that I find a solution to get available values of a multi-pick list by Apex coding.


Retrieving  available values of a multi-pick list

   The used function as below:

  public List<selectOption> getPickListValues(Sobject objectName, String fieldName, String firstValueLabel, String firstValue) {

            List<selectOption> options = new List<selectOption>();
            if (firstValueLabel != null) { //if first value
                options.add(new selectOption(firstValue, firstValueLabel)); //add the first option
            }
            Schema.sObjectType sobjectType = objectName.getSObjectType(); //get the sobject from schema
            Schema.DescribeSObjectResult sobjectDescribe = sobjectType.getDescribe(); //get the describe of sobject
            Map fieldMap = sobjectDescribe.fields.getMap(); //get a map of all  fields for sobject
            List pickListValues = fieldMap.get(fieldName).getDescribe().getPickListValues(); //get the list of picklist values for the field on the sobject
            for (Schema.PicklistEntry a : pickListValues) { //for all values in the picklist list
                if(a.getValue() != 'unknown' && a.getValue() != 'Other' )        
                    options.add(new selectOption(a.getValue(), a.getLabel())); //add the value and label to options
            }
            return options;
        }


  For eg:  getPickValues(new Account(), 'Select_List__c', 'All', 'All');

   Here my parent object is Account and the field is Select_List__c.

Using multi-pick list value in SOQL

   The query that I used as:

    [SELECT name FROM child__c WHERE Account__r.Select_List__c INCLUDES (:filter)]; 


References:

http://boards.developerforce.com/t5/Apex-Code-Development/How-to-retrieve-multi-select-picklists-using-includes-excludes/td-p/172210

http://boards.developerforce.com/t5/Apex-Code-Development/Looping-through-multi-select-picklist-values/td-p/401647 

NB: This is for my future reference only