How to create Multiple Select lookup in Class

Finance and Operations/AX
1

Hi,
I have created a class to clear delivery remainder by selecting PurchId in lookup and ItemId which have remainder >0 belongs to selected PurchId in another Lookup using Field Lookup, control.
Now I want to select multiple Item in Look up to clear the delivery remainder.

***Code
public void lookup_ItemId(FormStringControl _control1)
{
Query query = new Query();
QueryBuildDataSource queryBuildDataSource;
QueryBuildRange queryBuildRange;
//SysLookupMultiSelectCtrl sysLookupMultiSelect;
SysTableLookup sysTableLookup = SysTableLookup::newParameters(tableNum(PurchLine),
_control1);
sysTableLookup.addLookupField(fieldNum(PurchLine, ItemId));
queryBuildDataSource = query.addDataSource(tableNum(PurchLine));
queryBuildDataSource.addRange(fieldNum(PurchLine, PurchId)).value(fieldLookup.value());
queryBuildDataSource.addRange(fieldNum(PurchLine, RemainInventPhysical)).value(queryValue(“>0”));
queryBuildDataSource.addRange(fieldNum(PurchLine, RemainPurchPhysical)).value(queryValue(“>0”));

sysTableLookup.parmQuery(query);
sysTableLookup.performFormLookup();

}

please anyone suggest me an Idea.

regards,
monish