Conditional opening of a form from a report

In what might be termed a 'normal' report, one can cause a specific form (screen) to be opened with the current field in the report by pressing F6; this is default behaviour, but can be over-ridden by defining a specific form in the Target Form Name column of the Report Column Extension sub-level of the Report Columns form (this is documented). Thus for a part, normally the form LOGPART will be opened, but this can be changed to open a different form such as FLUSHERROR.

In more complicated reports that display different types of document in the same field (such as an order number or a delivery note number), the above mechanism does not work and so one has to define a special field that contains the name of the form to be opened. I wrote about this a few months ago but cleverly managed not to document how the given field is marked; this used to be undocumented, but recent versions of the Priority SDK devote a section to this, although as usual this is somewhat unclear.

In order to achieve this, for the report column in question, record the following settings in the Link/Input tab of the Report Columns-HTML Design sub-level of the Report Columns form:

• Link/Input Type = P
• Return Value Name (:HTMLACTION) = _winform
• Return Value Column# (:HTMLVALUE) = the number of the column containing the ENAME of the target form. Note: The column with the ENAME of the target form must have a Sort value.
• Internal Link Column# = same as :HTMLVALUE above.

I recently had to add a new wrinkle to the above. The report in question sometimes displayed part numbers but could also display text labels (the report in question is based on exploding a BOM but then adding values for variables such as 'shipping' at the end of the report); I wanted that clicking on the part name would bring up the LOGPART form, but that clicking on a text label would do nothing.

One can't use the standard specific form in the Target Form Name column as the given field is an expression. Using the _winform approach means that the 'column containing the ENAME' should be defined as = (STACK4.INTDATA = 0 ? 'LOGPART' : <something>) and a further hidden field be defined as EXEC.TYPE = 'F'. The '<something>' is a place holder intended for the text labels; I wasn't too sure what to place there at first.  

Initially I replaced <something> by ' ' (i.e. the null string), but then these extra lines did not appear as there is no entry in the EXEC table for ENAME = ' ' and TYPE = 'F'. I then replaced the empty string with 'F' (as I noted in a previous blog, there is a dummy form called F); this worked in the sense that the extra lines appeared, but clicking on the text label caused this dummy form to appear, which I did not want. My next attempt was to replace the condition on the EXEC.TYPE field with  = (STACK4.INTDATA = 0 ? 'F' : ''); this worked properly (i.e. no form opened when clicking on the text label) but seemed too fussy.

Glancing through the SDK one more time, I found a more elegant solution: EXEC.TYPE can be equal to 'F' and ENAME becomes = (STACK4.INTDATA = 0 ? 'LOGPART' : 'NULL'). This is documented  both in the 'Forms' chapter and the 'Reports' chapter of the SDK (to disable automatic access from a given column, specify the NULL form as the target form in the Form Column Extension form).

I learn something new every day.