X++ Code to create Lookup for DialogField in ax 2012 r3

class Dialoglookup

{

    Dialog       dialog;

    DialogField  dlgworkerid,dlgpurchase,dlgdate;

}

Public dialog dialog()

{

    FormStringControl control,controlname;

    ;

    dialog = new Dialog();

    dlgworkerid = dialog.addField(extendedTypeStr(HcmPersonnelNumberId));

    dlgpurchase = dialog.addfield(extendedTypeStr(UserId));

    dlgpurchase.value(curUserId());

    control = dlgworkerid.control();

    dlgdate  = dialog.addField(extendedTypeStr(TransDate));

    //controlname =dlgpurchase.control();

    control.registerOverrideMethod(methodStr(FormStringControl,lookup),methodStr(Dialoglookup,Worker_LookUp),this);

    //controlname.registerOverrideMethod(methodStr(FormStringControl,lookup),methodStr(Dialoglookup,name_lookup),this);

  return dialog;

}

public void Worker_LookUp(FormStringControl _control)

{

    Query                 query;

    QueryBuildDataSource  qbds;

    SysTableLookup sysTableLookup;

    ;

    query = new Query();

    query.addDataSource(tableNum(HcmWorker));

    sysTableLookup = SysTableLookup::newParameters(tablenum(HcmWorker),_control);

    sysTableLookup.addLookupfield(fieldNum(HcmWorker,PersonnelNumber),true);

    sysTableLookup.addLookupMethod(tableMethodStr(HcmWorker,name));

    sysTableLookup.parmQuery();

    sysTableLookup.performFormLookup();

}