请教飞哥！

afeng0712

如何判断SAFEARRAY的值是NIL？？/

meflying

(null safearray)


如果是nil，返回T，否则返回nil

afeng0712

飞哥，用VLA交出来的点是一变量，变量可求值得变体！



实际上两条线可能不相交，这时求变体的值会出错！所以需要先判断是否往下执行，但他的值是NIL，但是你上面那种判断不行！变体还不是表，(null 变体)始终为NIL！！！

meflying

不是很明白你的话，变量就是变体吧，只是不同的说法。。。


把你的程序和你要解决的问题都写上来吧

meflying

看看置顶的求交点的帖子，mccad的函数中就有判断是否存在交点情况的语句，可能是你要的吧

afeng0712

飞哥，该程序主要解决N条要打断的线被相交的M条线打断，可能存在有两不相交的情况：程序如下： (DEFUN C:BM (/ OC SS SA I J SS1 SSA P0)
(VL-LOAD-COM)
(SETQ OC (GETVAR "CMDECHO"))
(SETVAR "CMDECHO" 0)
(PROMPT "\n 选择要打断的线条:")
(SETQ SS (SSGET '((0 . "*LINE,ARC,CIRCLE,ELLIPSE"))))
(PROMPT "\n 选择与之相交的线条:")
(SETQ SA (SSGET '((0 . "*LINE,ARC,CIRCLE,ELLIPSE"))))
(SETQ J 0)
(WHILE (< J (SSLENGTH SA))
(SETQ SSA (VLAX-ENAME->VLA-OBJECT (SSNAME SA J)))
(SETQ I 0)
(WHILE (< I (SSLENGTH SS))
(SETQ SS1 (VLAX-ENAME->VLA-OBJECT (SSNAME SS I)))
(SETQ P0
(VLA-INTERSECTWITH
SS1
SSA
ACEXTENDNONE
)
)
(SETQ P0 (VLAX-VARIANT-VALUE P0))
(SETQ P0 (LIST (VLAX-SAFEARRAY-GET-ELEMENT P0 0)[如果不相交此处会出错，所以得先判断如果不存在交点就跳过下面语句执行下一循环]
(VLAX-SAFEARRAY-GET-ELEMENT P0 1)
)
)
(SETQ P0 (TRANS P0 0 1))
(SETQ P0 (OSNAP P0 "Int"))
(SETQ SS1 (LIST (SSNAME SS I) P0))
(COMMAND "_BREAK" SS1 "F" P0 "@")
(SETQ SSB (ENTLAST))
(SETQ I (1+ I))
)
(SETQ J (1+ J))
)
(SETVAR "CMDECHO" OC)
(PRINC)
)

BDYCAD

(DEFUN C:BM (/ OC SS SA I J SS1 SSA P0)
(VL-LOAD-COM)
(SETQ OC (GETvar "CMDECHO"))
(SETvar "CMDECHO" 0)
(PROMPT "\n ??要打?的??:")
(SETQ SS (SSGET '((0 . "*LINE,ARC,CIRCLE,ELLIPSE"))))
(PROMPT "\n ??与之相交的??:")
(SETQ SA (SSGET '((0 . "*LINE,ARC,CIRCLE,ELLIPSE"))))
(SETQ J 0)
(WHILE (< J (SSLENGTH SA))
(SETQ SSA (VLAX-ENAME->VLA-OBJECT (SSNAME SA J)))
(SETQ I 0)
(WHILE (< I (SSLENGTH SS))
(SETQ SS1 (VLAX-ENAME->VLA-OBJECT (SSNAME SS I)))
(SETQ P0
(VLA-INTERSECTWITH
SS1
SSA
ACEXTENDNONE
)
)

(if P0 (progn
(SETQ P0 (VLAX-VARIANT-VALUE P0))
(SETQ P0 (LIST (VLAX-SAFEARRAY-GET-ELEMENT P0 0);[如果不相交此??出?，所以得先判?如果不存在交?就跳?下面?句?行下一循?]
(VLAX-SAFEARRAY-GET-ELEMENT P0 1)
)
)
(SETQ P0 (TRANS P0 0 1))
(SETQ P0 (OSNAP P0 "Int"))
(SETQ SS1 (LIST (SSNAME SS I) P0))
(COMMAND "_BREAK" SS1 "F" P0 "@")
(SETQ SSB (ENTLAST))))
(SETQ I (1+ I))
)
(SETQ J (1+ J))
)
(SETvar "CMDECHO" OC)
(PRINC)
)

meflying

我5楼不是说了吗？仔细看看吧

xstlf

七楼BDYCAD的我试了一下。提示说; 错误: ActiveX 服务器返回错误: 索引无效。这是什么错误呀？

afeng0712

问题已处理！用上界可解决！