Diff bet poplist & combo box ?

Question

Hello Friends...
now i m learning forms .. can anyone tell me exact diff bet poplist & combo box..where we hv to exact use of poplist & combo box??
from help topics i get this much info only
Description
Specifies the display style for the list item, either poplist, combo box, or Tlist. The poplist and combo box styles take up less space than a Tlist, but end users must open the poplist or combo box to see list elements. A Tlist remains "open," and end users can see more than one value at a time if the list is large enough to display multiple values.

Answer 1

Hi,
when we add dynamically in list item..so we need to ADD_LIST_ELEMENT to add elements in list..There are different ways of populating the list item. Using ADD_LIST_ELEMENT is one of the method. However, the preferred method is to create a record group and populate the list using the record group using populate_group and populate_list (online help would certainly have some examples for this).
which trigger we write this ??Depends on the requirement. If you want the list to be populated when the form is loaded, you would be using when-new-form-instance trigger. However, if you want to filter the list based on some condition, you would write it in the WHEN-VALIDATE-ITEM trigger of the filter field / when-button-pressed trigger of the button which filters.
time how much values we can add ??I don't understand this. Is your question is "at a time how many values can be added"? then, there is no limit as such. Or, if your question is, "how much time it takes to add a value", it all depends on many factors like, network etc.
On the related note, it is not a good idea to use a list if you have many values (say more than 100 or so). In that case, you might want to use List of Values instead of Combobox/PopList.
-Arun