LookUp for a string field

Override the LookUp method in Form DS or Form design

public void lookup(FormControl _formControl, str _filterStr)
{
    Query query = new Query();
    QueryBuildDataSource queryBuildDataSource;
    QueryBuildRange queryBuildRange;

    SysTableLookup sysTableLookup = SysTableLookup::newParameters(tableNum(CEMContinuingEducation), _formControl);

    sysTableLookup.addLookupField(fieldNum(CEMContinuingEducation, CEMEducationType));
    sysTableLookup.addLookupField(fieldNum(CEMContinuingEducation, ContEducationCategoryId));

    queryBuildDataSource = query.addDataSource(tableNum(CEMContinuingEducation));
    queryBuildRange = queryBuildDataSource.addRange(fieldNum(CEMContinuingEducation, ContEducationCategoryId));
    queryBuildRange.value(CEMPersonContinuingEducation.ContEducationCategoryId);

    queryBuildDataSource.addSelectionField(fieldNum(CEMContinuingEducation, CEMEducationType));

    sysTableLookup.parmQuery(query);

    sysTableLookup.performFormLookup();

    //super(_formControl, _filterStr);

}