How to create field Id lookup in D365FO

Hi D365FO Team,

I am creating another blog here to know how to create table field Id Lookup.

Requirement - Show all VendTable field in lookup.

Solution/Steps

1) Create temprary table as shown in below screen with 2 fields.
Table name - TestFieldsListPreviewTMP
FieldName - use EDT fieldnameShort
FieldId  - use EDT Integer

Set Property - TableType = InMemory
Create Primary index on FieldId

2) Create new table TestLookupDSTable for formDatasource where you want to show table field lookup.

Add methods in above table-

Create lookupFields() method to insert all the field list from table buffer.

public static TestFieldsListPreviewTMP  lookupCustomFields(Common   _common)
{
        var dictTable = new DictTable(_common.TableId);
        FieldId fieldId = dictTable.fieldNext(0);

        TestFieldsListPreviewTMP  fieldListPreview;

        while (fieldId && ! isSysId(fieldId))
        {
            fieldListPreview.FieldId = fieldId;
            fieldListPreview.FieldName = fieldId2PName(_common.tableId, fieldId);
            fieldListPreview.insert();
            fieldId = dictTable.fieldNext(fieldId);
        }
        return fieldListPreview;
}

public static void performLookup(Common _common, FormControl _formControl)
{

     SysTableLookup sysTableLookup =         SysTableLookup::newParameters(tablenum(TestFieldsListPreviewTMP), _formControl);

        Query query = new Query();
        QueryBuildDataSource queryBuildDataSource;
        queryBuildDataSource = query.addDataSource(tablenum(TestFieldsListPreviewTMP));
        queryBuildDataSource.addSortField(fieldNum(TestFieldsListPreviewTMP, FieldId), SortOrder::Ascending);

        sysTableLookup.addLookupfield(fieldnum(TestFieldsListPreviewTMP, FieldId), true);
        sysTableLookup.addLookupfield(fieldnum(TestFieldsListPreviewTMP, FieldName));
        sysTableLookup.parmQuery(query);

        TestFieldsListPreviewTMPfieldListTMP;

        fieldListTMP = TestForDataSourceTable::lookupCustomFields(_common);

        //TestVend2CustMapping is a form data source table.
        sysTableLookup.parmTmpBuffer(fieldListTMP);
        sysTableLookup.performFormLookup();

    }

//Populate field name 
public static FieldName predictFieldName(TableId _tableId, FieldId _fieldId)
{
        return fieldId2PName(_tableId, _fieldId);
}

public void modifiedField(FieldId _fieldId)
{
        super(_fieldId);
        switch(_fieldId)
        {
            case (fieldNum(TestLookupDSTable,FieldIdVend )) :           
                this.FieldNameVend = TestLookupDSTable::predictFieldName(tableNum(VendTable), this.FieldIdVend);             

                break;
            default:

        }
}


3) Create new form and add TestLookupDSTable as data source and override datasource field lookup method and write below code.

public void lookup(FormControl _formControl, str _filterStr)
{
     VendTable   vendTable;

     TestLookupDSTable::performLookup(vendTable, _formControl);

}

Result -