Create drawing dimension with web.link

Hi everyone, we wanna develop a function whitch would auto create a dimension to represent the length of specific edge in drawing mode. I found a few descriptions in web.link user guide.

"The method pfcEmptyDimensionSense.Create() creates a new
dimension sense associated with the type DIMSENSE NONE. The sense field is
set to Type In this case no information such as location or direction is needed to
describe the attachment points. For example, if there is a single attachment which
is a straight line, the dimension is the length of the straight line."

There comes two question. First, is there supported API to get every edge's length so we could make comparison to find out the longest edge. Second, if we could find the longest one, is there some snipped code could be refereced  to really build up the dimesion like below ?