Form lookups and how they work

There are few different ways to achieve a lookup field on a form.

1) Create an Extended data type – EDT123
2) Create a table Table123
3) Add EDT123 to the table and the Description EDT field
4) Go back to the EDT and create a relation between table123.EDT123 and the EDT123
5) Automatically when the EDT field is added to another table lets say CustTable a lookup displaying the values from table123 will be displayed in the drop down.
6.) Now lets say you want to add the description field to the lookup as well. Add the description field to the AutoLookup field group on the table. Now the lookup will display EDT123 and the description field from table123.

That is a simple way to create a lookup
Another way to create a lookup is to write a dynamic lookup on the table in which the data is coming from. This method will be a static method and will require the passing of arguments – typically the formstringcontrol that is to be the point of lookup. I prefer this method and use it often

This a very simple example of a static lookup from a table

static void lookupTruckLoadIdEndingInv(FormStringControl _ctrl)
{
SysTableLookup sysTableLookup = SysTableLookup::newParameters(tablenum(WfsRMTruckLoadStatus), _ctrl);
Query query = new Query();
QueryBuildRange qbr;
;

query.addDataSource(tablenum(WfsRMTruckLoadStatus));

sysTableLookup.addLookupfield(fieldnum(WfsRMTruckLoadStatus, truckLoadId ));

query.dataSourceTable(tablenum(WfsRMTruckLoadStatus)).addRange(fieldnum(WfsRMTruckLoadStatus,retTransferred)).value(SysQuery::value(NoYes::No));

sysTableLookup.parmQuery(query);
sysTableLookup.performFormLookup();
}

Joins can be peformed as well to pull back the desired data so you are not limited to querying on one table to return the proper data back to your lookup

static void lookupSettledTruckLoadIdCashier(FormStringControl _ctrl)
{
SysTableLookup sysTableLookup = SysTableLookup::newParameters(tablenum(WfsRMTruckLoadHeader), _ctrl);
Query query = new Query();
QueryBuildRange qbr;
queryBuildDataSource qbdsTruckLoadStatus,qbdsTruckLoadHeader,qbdsTenderSlipHeader;
;

qbdsTruckLoadHeader = query.addDataSource(tablenum(WfsRMTruckLoadHeader));

qbdsTruckLoadStatus = qbdsTruckLoadHeader.addDataSource(tablenum(WfsRMTruckLoadStatus));
qbdsTruckLoadStatus.relations(true);

qbdsTruckLoadStatus.addRange(fieldnum(WfsRMTruckLoadStatus,settled)).value(enum2str(NoYes::No));
qbdsTruckLoadStatus.addRange(fieldnum(WfsRMTruckLoadStatus,HHTruckLoadIdEnded)).value(enum2str(NoYes::Yes));
qbdsTruckLoadStatus.addRange(fieldnum(WfsRMTruckLoadStatus,RetTransferred)).value(enum2str(NoYes::Yes));

qbdsTenderSlipHeader = qbdsTruckLoadStatus.addDataSource(tablenum(wfsRMTenderSlipHeader));
//qbdsTenderSlipHeader.relations(true);
qbdsTenderSlipHeader.addLink(fieldnum(WfsRMTruckLoadStatus, truckLoadId),fieldnum
(wfsRMTenderSlipHeader, truckLoadId));
qbdsTenderSlipHeader.joinMode(joinMode::NoExistsJoin);

sysTableLookup.addLookupfield(fieldnum(WfsRMTruckLoadHeader, truckLoadId));
sysTableLookup.addLookupfield(fieldnum(WfsRMTruckLoadHeader, routeId));
sysTableLookup.parmQuery(query);
sysTableLookup.performFormLookup();
}

Another way is to create an actual form and call it in a method on the table. You will still need to pass in the formstringcontrol object but in this case you will be calling an actual existing form that you have created. Now why do this ? Well one reason may be that you want to be able to filter on a specific field in the lookup that maybe you could not on a typical lookup or maybe you need to add a field to the lookup that would otherwise not be possible like you can add a display method to a lookup but maybe you want to see the field referenced in the display method and have the ability to sort on the field or filter on the field.

For example like DirPartyTable.Name

Sure you can access it using a display method but maybe you want to see it in your lookup and be able to filter on it. So you will create a form and call it like a lookup so you can have all the the filtering of a standard form

public client static void WfsRMlookupEmplIdCashier(Object _ctrl)
{
Args args;
FormRun formRun;
;

args = new Args();
args.name(formstr(WfsRMEmplIdLookupCashier));
args.caller(_ctrl);
formRun = classfactory.formRunClass(args);
formRun.init();
_ctrl.performFormLookup(formRun);
}

The standard lookups present in AX like the item number lookup and the customer lookup are very interesting in that you only see one field on the relation but no fields in the autolookup. In these cases the lookup fields are coming from the standard indexes on the table. Take note of what you see in the itemId lookup when unchanged and then reference the indexes coincidence not really. this can apply to any new lookup you create as well.
You can also override the lookup on the datasource - field of a form or an actual field string edit control on a form and perform a lookup

Form design object

public void lookup()
{

SysTableLookup sysTableLookup;
Query query=new Query();
QueryBuildDataSource qbds;

;
sysTableLookup=SysTableLookup::newParameters(tablenum(Dimensions),this);

sysTableLookup.addLookupfield(fieldnum(Dimensions,Num));
sysTableLookup.addLookupfield(fieldnum(Dimensions,Description));

qbds = query.addDataSource(tablenum(Dimensions));

qbds.addRange(fieldnum(Dimensions,DimensionCode)).value(queryValue(COSAllowedDimensions::
getAllowedDimensionValue(sysDim)));

sysTableLookup.parmQuery(query);
sysTableLookup.performFormLookup();
}

//Lookup from a field on the form data source

public void lookup(FormControl _formControl, str _filterStr)
{
Args args;
FormRun formRun;
SysTableLookup sysTableLookup = sysTableLookup::newParameters(tablenum(InventTable),_formControl);
Query query = new Query();
QueryBuildDataSource queryBuildDataSource;
QueryBuildRange queryBuildRange;
;
sysTableLookup.addLookupfield(fieldnum(InventTable,ItemID));
sysTableLookup.addLookupfield(fieldnum(InventTable,ItemName));
sysTableLookup.addLookupfield(fieldnum(InventTable,ItemGroupID));
sysTableLookup.addLookupfield(fieldnum(InventTable,NameAlias));
sysTableLookup.addLookupfield(fieldnum(InventTable,ItemType));
sysTableLookup.addLookupfield(fieldnum(InventTable,DimGroupID));

queryBuildDataSource = query.addDataSource(tablenum(Inventtable));
queryBuildRange = queryBuildDataSource.addRange(fieldnum(InventTable,ItemGroupID));
//FGL, FGR, Returns
queryBuildRange.value('xxx');

queryBuildRange = queryBuildDataSource.addRange(fieldnum(InventTable,ItemGroupID));
queryBuildRange.value('yyy');

queryBuildRange = queryBuildDataSource.addRange(fieldnum(InventTable,ItemGroupID));
queryBuildRange.value('Returns');

sysTableLookup.parmQuery(query);
sysTableLookup.performFormLookup();

}