How to Link to Object in a System Form

Hi expert,

i need to ask you something about the correct way to connect to objects in a system form.

I want to manage standard "Quotation Form".

I found the way to read and write values form field in the header of document, like "CardCode", "CardName", "Project" and so on.

Read the values from these fields, it's easy:

sCardCode = oQuotationForm.DataSources.DBDataSources.Item(0).GetValue("CardCode", 0);

sProject = oQuotationForm.DataSources.DBDataSources.Item(0).GetValue("Project", 0);

As you can see, I can use a direct reference to OQUT field "CardCode" in the GetValue() method:  GetValue("CardCode", 0)

Problem is that:

How can I access data from the grid in the main body of document?

I think the token i need to use is:

oQuotationForm.DataSources.DBDataSources.Item( OBJECT_INDEX ).GetValue( INDEX, RECORDNO )

But, how I can find the OBJECT_INDEX, INDEX and RECORDNO? Are these values in the left corner of SAP client?

Thanks for your tips.

Jonny Cortonicchi