Just add the below code in lookup() of StringEdit control in Form to get the Business Unit Lookup:
public void lookup()
{
Query query;
SysTableLookup sysTableLookup;
super(); //DimAttributeOMBusinessUnit is a View
sysTableLookup = SysTableLookup::newParameters(tableNum(DimAttributeOMBusinessUnit), this); sysTableLookup.addLookupfield(fieldNum(DimAttributeOMBusinessUnit, Value));
sysTableLookup.addLookupfield(fieldNum(DimAttributeOMBusinessUnit, Name)); query = new Query(); query.addDataSource(tableNum(DimAttributeOMBusinessUnit)); sysTableLookup.parmQuery(query); sysTableLookup.performFormLookup(); }