multi select lookup in ssrs report dialog

class ALE_ExpenseReportUIBuilder extends SysOperationAutomaticUIBuilder//SrsReportDataContractUIBuilder
{
    ALE_ExpenseReportContract           contract;
    SysLookupMultiSelectGrid            multiSelect;
}

//
public void build()
{

    contract = this.dataContractObject();

    this.addDialogField(methodStr(ALE_ExpenseReportContract,parmFromDate),contract);
    this.addDialogField(methodStr(ALE_ExpenseReportContract,parmToDate),contract);
    this.addDialogField(methodStr(ALE_ExpenseReportContract,parmWrkCtrId),contract);
    //this.addDialogField(methodStr(ALE_ExpenseReportContract,parmWrkCtrGroupId),contract);
    this.addDialogField(methodStr(ALE_ExpenseReportContract,parmCheck),contract);
    //super();
}

//
private void lookupWrkctrId(FormStringControl    _formStringControl)
{
    Query                   query;
    QueryBuildDataSource    datasource;
    QueryBuildRange         queryBuildRange;
 
    if(_formStringControl != null)
    multiSelect     = SysLookupMultiSelectGrid::construct(_formStringControl,_formStringControl);
    //SysTableLookup          sysTableLookup      = SysTableLookup::newParameters(tableNum(WrkCtrTable), _formStringControl);

    query = new Query();
    datasource = query.addDataSource(tableNum(WrkCtrTable));
    queryBuildRange = datasource.addRange(fieldNum(WrkCtrTable,WrkCtrType));
    //queryBuildRange.value(strFmt("%1, %2", Global::enum2int(WrkCtrType::Machine), Global::enum2int(WrkCtrType::Tool)));
    //sysTableLookup.addLookupfield(fieldNum(WrkCtrTable,WrkCtrId));
    //sysTableLookup.parmQuery(query);
    //sysTableLookup.performFormLookup();
    query.dataSourceTable(tableNum(WrkCtrTable)).addSelectionField(fieldNum(WrkCtrTable, WrkCtrId));
    query.dataSourceTable(tableNum(WrkCtrTable)).addSelectionField(fieldNum(WrkCtrTable, Name));
 
    multiSelect.parmQuery(query);
    multiSelect.run();




//sysTableLookup.parmQuery(query);



}

//
public void postBuild()
{
    DialogField         resource;
    DialogField         resourceGroup;
    super();
    resource = this.bindInfo().getDialogField(this.dataContractObject(),
            methodStr(ALE_ExpenseReportContract,parmWrkCtrId));
    //resourceGroup = this.bindInfo().getDialogField(this.dataContractObject(),
           // methodStr(ALE_ExpenseReportContract,parmWrkCtrGroupId));
    resource.registerOverrideMethod(methodstr(FormStringControl, lookup), methodstr(ALE_ExpenseReportUIBuilder, lookupWrkctrId ), this);
    //resourceGroup.registerOverrideMethod(methodstr(FormStringControl, lookup), methodstr(ALE_ExpenseReportUIBuilder, lookupWrkctrGroupId ), this);
}
//
public void postRun()
{
    //super();
}


contract class// parm method use list

public List parmWrkCtrId(List _resouce = resource)
{
    resource = _resouce;
    return resource;
}

in Dp get the list value as follow

ListIterator                resourceListIt;

resourceListIt = new ListIterator(contract.parmWrkCtrId());

 while (resourceListIt.more())
 {
         resourceListIt.value();
..
..
     resourceListIt.next();    


}