帮忙看看下面的短程序问题在哪里，我想知道两条直线怎么延伸到相交

wangyancai

Sub lengthenline()
Dim lineobj As AcadLine
Dim p1(0 To 2) As Double
Dim p2(0 To 2) As Double
p1(0) = 50: p1(1) = 50: p1(2) = 0
p2(0) = 60: p2(1) = 60: p2(2) = 0
setlineobj1 = ThisDrawing.ModelSpace.AddLine(p1, p2)
lineobj1.Update
Dim p3(0 To 2) As Double
Dim p4(0 To 2) As Double
p3(0) = 40: p3(1) = 80: p3(2) = 0
p4(0) = 100: p4(1) = 80: p4(2) = 0
Set lineobj2 = ThisDrawing.ModelSpace.AddLine(p3, p4)
lineobj1.EndPoint = lineobj2
lineobj1.Update
End Sub