How to use Control FIle?

Hi Experts,

I want to use Control FIle(It is a control of format designer) to upload a excel, and extract data of excel. However, I set some attrubutes for the control File, details as follows:

Transfer direction: Upload

File Directory: keep default(should be Run directory)

Input: a field of dbdict

I don't know how it work. but I guess that the control FIle is just responsibile for uploading file to RUN directory, the field of the dbdict save the file name. If need to get the file, it is neccesary to read the file from RUN directory according to the file name saved in the dbdict. is it correct?

Please help?

 

Thanks and best regards