multi table lookup ax 2009

public void lookup()
{
    Query                   query = new Query();
    QueryBuildDataSource    qbdsItem;
    QueryBuildDataSource    qbdsInventTableModule,qbdsInvent;
    QueryBuildDataSource    qbdsInventItemLocation;
    QueryBuildRange         qbrModuleType;
    SysMultiTableLookup     sysTableLookup;
    ;
    qbdsItem = query.addDataSource(tableNum(prodBom));
    qbdsInventTableModule = qbdsItem.addDataSource(tableNum(inventdim), "Purch");
    qbdsInventTableModule.relations(true);
    if(S3RejectionLine_ProdId.valueStr())
    {
        qbdsItem.addRange(fieldnum(prodBom,Prodid)).value(S3RejectionLine_ProdId.valueStr());
    }
    qbdsInventTableModule.fetchMode(QueryFetchMode::One2One);
    sysTableLookup = SysMultiTableLookup::newParameters(this, query);
    sysTableLookup.addLookupField(fieldNum(prodBom, recid));
    sysTableLookup.addLookupField(fieldNum(prodBom, ItemId),1,false,'Itemid');
    sysTableLookup.addLookupMethod('ItemName',1,'ItemName');
    sysTableLookup.addLookupField(fieldNum(inventdim, InventSizeId), 2, false, "InventSizeId");
    sysTableLookup.addLookupField(fieldNum(inventdim, InventLocationId), 2,false,"InventLocationId");
    sysTableLookup.addLookupField(fieldNum(inventdim, configId), 2,false,"configId");

    sysTableLookup.performFormLookup();
}