Override form control Lookup using extensions in D365FO / AX 7.0

In D365FO we have a bunch of events to subscribe on a form control level:

right click on lookup event of control to subscribe the event and paste in class.

[FormControlEventHandler(formControlStr(PayrollEmployerTaxRegion, Overview_StateId), FormControlEventType::Lookup)]

    public static void Overview_StateId_OnLookup(FormControl sender,FormControlEventArgs e)

    {

                  // write your logic here

    }

Now to cancel parent event, D365FO provide a class FormControlCancelableSuperEventArgs

You can cancel the parent(Original event with below code)

        FormControlCancelableSuperEventArgs ce = e asFormControlCancelableSuperEventArgs;

        //cancel super() to prevent error.

        ce.CancelSuperCall();

// Here is the complete code sample to override form lookup and cancel the original code.

[FormControlEventHandler(formControlStr(PayrollEmployerTaxRegion, Overview_StateId), FormControlEventType::Lookup)]

    public static void Overview_StateId_OnLookup(FormControl sender,FormControlEventArgs e)

    {

        SysTableLookup      sysTableLookup  =SysTableLookup::newParameters(tableNum(LogisticsAddressState), sender);

        Query               query           = new Query();

        // Filter lookup to only show US states

        query.addDataSource(tableNum(LogisticsAddressState)).addRange(fieldNum(LogisticsAddressState, CountryRegionId)).value(LogisticsAddressCountryRegion::findByISOCode(SysCountryRegionCode::countryInfo(curext())).CountryRegionId);

        // Sort the lookup by state Id

        query.dataSourceTable(tableNum(LogisticsAddressState)).addOrderByField(fieldNum(LogisticsAddressState, StateId), SortOrder::Ascending);

        // Add fields

        sysTableLookup.addLookupfield(fieldNum(LogisticsAddressState, StateId));

        sysTableLookup.addLookupfield(fieldNum(LogisticsAddressState, Name));

        // Run lookup

        sysTableLookup.parmQuery(query);

        sysTableLookup.performFormLookup();

        FormControlCancelableSuperEventArgs ce = e asFormControlCancelableSuperEventArgs;

        //cancel super() to prevent error.

        ce.CancelSuperCall();

    }