i wanna add method as primarykey on filedId

i am getting error on this method

so, please i am looking for solution.

========================================================

display fieldId primaryFieldId()
{
;
SubjectsTable = new SubjectsTable(this.)
return dictTable.primaryKeyField();
}

What is the error you are getting?

Code example

static void primaryKeyField(Args _args)

{

DictTable dictTable = new DictTable(tableNum(InventTable));

FieldId fieldId;

fieldId = dictTable.primaryKeyField();

}