smartgwt remove duplicate values from selectitem

Does anybody know how to hide duplicate values (course names) from SelectItem?

My code:

SelectItem  courseOfferingItem = new SelectItem ("courseOffering.id", "Course Offering");
courseOfferingItem.setOptionDataSource(CoursesOfferingDS.getInstance());
courseOfferingItem.setDisplayField("courseOffering.courseName");
c开发者_StackOverflowourseOfferingItem.setShowDisabled(false);

SelectItem is showing courses CBNST, FIT, FIT, DS but I don't want to show FIT two times.

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you must use LinkedHashMap to populate your ComboBox items. it will be easy to set and manage and duplicate values will be removed. it can be done by.... SelectItem courseOfferingItem = new SelectItem(); courseOfferingItem.setValueMap(linedHashMap);

and linkedHashMap will contain your item id and item value...hope it will be useful to you...