Custom Lookup and Group By

问题

TLDR: Why group by clauses are disabled in lookups when the field using the lookup is not empty?

I want to do a custom lookup on a field in a form. The table CTable looks like this:

Val Spec
------------
A   alpha
A   beta
A   gamma
B   delta
C   epsilon

The look up only concerns the Val column which is defined using an EDT with a basic relationship on it: Val == CTable.Val

The lookup obviously gives me a list like this:

A
A
A
B
C

Let's to a group by to get rid of all the duplicated As, I thought! Something along the lines of:

QueryBuildDataSource.orderMode(OrderMode::GroupBy);
QueryBuildDataSource.addGroupByField(fieldNum(CTable, Val));

Now comes the strange behaviour I have and the actual point of my question. On an empty field, the group by is correctly executed and I get this:

A
B
C

Now let's select "A" in the lookup, then perform the lookup again because I wanted to click on "B" instead. The group by is now disabled for unknown reasons and I get the same look up results as the first I had before.

Why is it so? How can I overcome that?

回答1:

Same question and usefull answer: http://dynamicsuser.net/forums/t/63438.aspx

You can disable this behavior by setting useLookupValues in SysTableLookup to false. Unfortunately I don't know exactly why AX does that. I suspect that it changes OrderMode to OrderBy.

回答2:

I had the same problem yesterday.

I guess this code is in "init" maybe?

QueryBuildDataSource.orderMode(OrderMode::GroupBy);
QueryBuildDataSource.addGroupByField(fieldNum(CTable, Val));

I had to add my "GroupBy" code (above) to the executeQuery method, becuase the following line was removing the groupBys from my query (I checked this using breakpoints);

qbsSum.sortClear();

If you use breakpoints I would expect your GroupBy options are being cleared before the query executes again.

回答3:

I had the same problem. This helped me:
sysTableLookup.parmUseLookupValue(False);

来源：https://stackoverflow.com/questions/11453756/custom-lookup-and-group-by