Dynamic table with dynamic drop-down list values

Question

Hi,
I need to display a dynamic table with 2 columns on an interactive form.
My Context is defined as below:
Root
StudentData     0..n
StudentName
StudentCourses     0..n
Text
Value
The 1st column should display student name, 2nd column should display student courses. The courses will be different for each student. I populated the context properly. I checked it by printing them. My DDL is bound to "Student Courses".
When there is one row -> The DDL is populated with the courses of student 1 (as there is only one).
When there are more rows -> The DDLs for all the students are populated with all the courses of all the students.
I want to see the data populated like:
TEXTFIELD    DROP-DOWN LIST
Student 1------Student1-Course1
Student1-Course2
Student1-Course3
Student 2------Student2-Course1
Student2-Course2
Student2-Course3
I tried to do this in plain web dynpro using SVS.. it is also working similarly.
I have set the singleton property of nodes "StudentData" and "StudentCourses" to false.
Could any one tell me where I am going wrong?
Thanks
Ram

Answer 1

Ram,
I'm not sure how much this will help, but I know I had the same problem as you when I tried to get a similar thing working, but I can't remember which of the many changes I made fixed the problem, so I'll just show you my code and perhaps you can see if anything is different than yours.
Here's where I'm creating my dropdown - in my case EastNew_RegOut is the same as your StudentData, and RateTypeDropValues is the same as your StudentCourses (the comments in the code are not meant to sound bossy to you, this is actually an example piece of code that other developers in my company "steal", so I have to put very specific instructions in there!):
int nodeSize = wdContext.nodeEastNew_RegOut().size();
for (int i = 0; i < nodeSize; i++) {
     //create an element called "table", that's the element at i.  So, basically it's a row.  Maybe I should have
     //called it "row" instead of table.
     IPublicDeviceExchange.IEastNew_RegOutElement table = (IPublicDeviceExchange.IEastNew_RegOutElement)wdContext.nodeEastNew_RegOut().getElementAt(i);
     //this line of code just executes an rfc that finds out what rates need to be in the dropdown for this particular row
     executeRateTypeDropdown(rateCategory, table.getNum(), wdContext.currentEastNew_MeterOutElement().getReggrp());
     //clear out what's already in there before we re-populate it.
     table.nodeRateTypeDropValues().invalidate();
     //now, I'm looping through all the values in the *actual* rate type dropdown (the one that's an RFC, populated by the above "execute" method)
     for (int j = 0; j < wdContext.nodeEastRatetype_DropdownOut().size(); j++) {
          //for each element in the *actual* Rate type dropdown, I'm going to create an element in my node that I created
          //and set the values from the *actual* one as the values in my node.
                    IPublicDeviceExchange.IRateTypeDropValuesElement element = wdContext.createRateTypeDropValuesElement();
          IPublicDeviceExchange.IEastRatetype_DropdownOutElement rateTypeOut = (IPublicDeviceExchange.IEastRatetype_DropdownOutElement)wdContext.nodeEastRatetype_DropdownOut().getElementAt(j);
          element.setText(rateTypeOut.getText());
          element.setValue(rateTypeOut.getRatetype());
          //here's another key - notice how I don't say wdContext.nodeRateTypeDropValues() - it's the one that's
          //directly off that table I created earlier - the thing that's essentially a row in my newReg table.
          //So, what I'm doing here is adding that new element I created to the dropdown FOR THAT ROW!               
          //(btw, if you're trying to duplicate this, and this method does not exist for your "table" object, it's
          //probably because you didn't listen to me above and you didn't create your node with the singleton property
          //set to false.)
          table.nodeRateTypeDropValues().addElement(element);
As for my layout... my table is bound to the EastNew_RegOut node, and the column with the dropdown is bound to RateTypeDropValues.Value  (that's probably obvious, but there you have it anyway)
Finally, in my context, EastNew_RegOut is singleton = true (I was surprised about this, actually, I would have assumed it was false) with a selection of 0..1 and RateTypeDropValues has singleton set to false with a selection of 0..1
I hope that helps to some degree!
Jennifer