Hi I want to populate dropdown field on my form dynamically.I am on appian 7.2

Hi I want to populate dropdown field on my form dynamically.I am on appian 7.2
I am using following code
importScript('/plugins/servlet/FormsExt.js');
FormAPI.populateDropdown("txtMaterialCode", ["getMaterialCodeMappingExpRule","Carton","No"]);

Here
getMaterialCodeMappingExpRule is an expression rule which takes two parameters.


When I execute this code i get following error
"Unable to get value of the property 'options': object is null or undefined"

Any pointer to this will really be helpfull....

OriginalPostID-105563

OriginalPostID-105563