Currently Used Database fields on the report

Similar problem is how to retrieve all fields that are used on the report:

//'---------------------------------------------------------
//

// GetCurrentlyUsedDatabaseFields
//

// ICollection
// Get all used db fields from the report.
//
//'---------------------------------------------------------
private ICollection GetCurrentlyUsedDatabaseFields()
{
SortedList sortedlist = new SortedList();
string strShortFieldName;
Fields fields = _reportClientDocument.DataDefinition.ResultFields;
foreach(Field field in fields)
{
if(field.Kind == CrFieldKindEnum.crFieldKindDBField)
{
char period = '.';
int periodIndex = field.FormulaForm.IndexOf(period);
// parse out table and field name
strShortFieldName = field.FormulaForm.Substring(periodIndex+1, field.FormulaForm.Length-(periodIndex+2));
sortedlist.Add(field.FormulaForm, strShortFieldName);
}
}
return sortedlist;
}