FDK : element order, prop, ID?

Question

Hello,
I need to develop an automate to get prop of an element before an action and to set it after the action.
Before an action, it will search all P elements of the document that are before B elements. P is Paragraph (pgf).
Rbody
--B
--P (this one will not be good)
Rbody
--P (this one will be good)
--B
So, i want to get all the ID and prop of P elements that are before B elements.
I have tried a lot of things like go from P to P and on each P find the next sibling element and check if it's B element :
//fdk guide code + custom
F_ObjHandleT docId, pgfId, nsibId;
StringT b;
b=F_StrCopyString((StringT)"B");
docId = F_ApiGetId(0, FV_SessionId, FP_ActiveDoc);
pgfId = F_ApiGetId(FV_SessionId, docId, FP_FirstPgfInDoc);
while (pgfId)
nsibId = F_ApiGetId(docId, pgfId, FP_NextSiblingElement)
if(F_StrCmpN(F_ApiGetString(docId, nsibId , FP_Name), b, F_StrLen(b)==0)
F_Printf(NULL, "I'M VERY HAPPY\n");
pgfId = F_ApiGetId(docId, pgfId, FP_NextPgfInDoc);
it doesn't work, nsibId is 0.
it seems that i need to make a selection of the text but i'm not sure...
I don't well understand the logic to navigate through a document.
Do you know how to make this?
Thank you,
Alexandre

Answer 1

Hi Alexandre,
You are going about this the wrong way. If you are attempting to navigate a structure tree, you need to start with element IDs, not paragraph IDs. Basically, you should:
1 - Get the ID of the flow that contains the structure tree, maybe something like:
flowId = F_ApiGetId(FV_SessionId, docId, FP_MainFlowInDoc);
2 - Get the ID of the highest-level element in the flow, something like:
elemId = F_ApiGetId(docId, flowId, FP_HighestLevelElement);
... then you can use the FP_FirstChildElement, FP_NextSiblingElement, etc. properties of the elemId to walk through the tree. You can't call FP_NextSiblingElement on a paragraph ID because this is an element property only... paragraphs have no concept of parents, children, and siblings.
Also, to get the name of an element, you need to get the name of its underlying element definition. Something like:
F_ObjHandleT elemDef;
StringT elemName;
elemDef = F_ApiGetId(docId, elemId, FP_ElementDef);
elemName = F_ApiGetString(docId, elemDef, FP_Name);
...in other words, you can't get the tag name directly from the element. The name is a property of the element definition in the imported EDD.
Russ