How to filter the records in dialog field values ?

The following example class is to filter the records in a dialog fields

class TestDialogFields

{

    Dialog                       dialog;   

    DialogField              emplIdField;

}

Dialog showDialog()

{

    FormRun        formRun;

    ;

    dialog         = new Dialog('Dialog fields test');   

    emplIdField = dialog.addField(typeId(emplid));

    dialog.run(true);

    dialog.formRun().controlMethodOverload(true);

    dialog.formRun().controlMethodOverloadObject(this);

    return  dialog;

}

public void Fld1_1_lookup()

{

    FormStringControl        control               = dialog.formRun().controlCallingMethod();

    SysTableLookup          sysTableLookup =  SysTableLookup::newParameters(tablenum(EmplTable), control);

    Query                         query                = new Query();

    QueryBuildDataSource                          queryBuildDataSource;

    EmplTable                                            EmplTable;

    ;

   

    sysTableLookup.addLookupfield(fieldnum(EmplTable, EmplId));

    sysTableLookup.addLookupfield(fieldnum(EmplTable,EmplIdentNumber ));

    queryBuildDataSource = query.addDataSource(tablenum(EmplTable));

    queryBuildDataSource.addRange(fieldnum(EmplTable,EmplId)).value(queryRange("1000","2000"));

    sysTableLookup.parmQuery(query);

    sysTableLookup.performFormLookup();

}

public static void main(Args args)

{

     TestDialogFields testDialogFields = new TestDialogFields();

     ;

     testDialogFields.showDialog();

}