Generate Ax lookup in enterprise portal axapta

AxLookup is used in data entry pages to help the user select a valid value for a field that references keys from other tables. In Enterprise Portal, lookups are metadata-driven by default, and they are automatically enabled for fields, based on the relationship that is defined in metadata in the AOT.
An example is the customer group lookup on the customer creation page. The extended data type (EDT) and table relationship metadata in the AOT define a relationship between the customer table and the customer group table; therefore, a lookup is rendered so that the user can select a customer group in the customer group field when creating a customer record. You don’t need to write any code to enable this behavior—it happens automatically.

 void dataSetLookup(SysDataSetLookup sysDataSetLookup)  
  {  
 if (custTable.CountryRegionId)  
 { sysDataSetLookup.parmQuery().dataSourceNo(1).addRange( fieldnum(AddressZipCode,CountryRegionId)).value(queryValue(custTable.CountryRegionId));  
 }  
 if (custTable.State)  
  {  
 sysDataSetLookup.parmQuery().dataSourceNo(1).addRange( fieldnum(AddressZipCode,State)).value(queryValue(custTable.State));  
 }   
 if (custTable.County)  
 {   
 sysDataSetLookup.parmQuery().dataSourceNo(1).addRange( fieldnum(AddressZipCode,County)).value(queryValue(custTable.County));  
 }  
 }