To obtain a list of valid search interfaces in .NET, use the Navigation.ERecCompoundSearchKeys property.
The following example shows how the Navigation.ERecCompoundSearchKeys property can be used to obtain a list of search interface keys:
ERecCompoundSearchKeyList keylist = nav.ERecCompoundSearchKeys;
for (int i=0; i < keylist.Count; i++) {
// Get specific search interface key
ERecCompoundSearchKey key =
(ERecCompoundSearchKey) keylist.Key(i);
String name = key.Name;
boolean active = key.IsActive();
}