I am needing to extend vertical lines to horizontal lines but the issue I am having is that my extend operation extends the vertical line to the first closest horizontal line it comes across and not the intended selected horizontal line. How do I correct this? In my code I have the horizontal selected and the vertical line selected and then use boolstatus = swSketchMgr.SketchExtend(0#,0#,0#).
Please read the documentation. SketchExtend goes to the first entity it meets, not to some selected entity. If you want to go past the first entity, call multiple times (per the Remarks in the API help).