用户输入：选择两行

Question

我开始使用/写入autocad lisp。
以下是我在互联网上找到的代码。作为一个初学者，我想修改它，而不是选择（单行）line1和line2，我想要做多行选择（选择两行）。任何想法？

;------------------------------------------------------------------------ 
;- Command: midpts_line() 
;- 
;- Draws a line between the midpoints of two lines. 
;- 
;- Copyright 2008 Jeff Winship. All rights Reserved. 
;----------------------------------------------------------------5/3/2008 
(defun c:midpts_line() 
    ;-- Select the lines 
    (setq line1 (car (entsel "\nSelect the first line: "))) 
    (setq line2 (car (entsel "\nSelect the second line: "))) 

    ;-- Get the endpoints of the first selected line 
    (setq pt1 (cdr (assoc 10 (entget line1)))) 
    (setq pt2 (cdr (assoc 11 (entget line1)))) 

    ;-- Get the endpoints of the second selected line 
    (setq pt3 (cdr (assoc 10 (entget line2)))) 
    (setq pt4 (cdr (assoc 11 (entget line2)))) 

    ;-- Find the midpoints of the lines 
    (setq mid1 (midpt pt1 pt2)) 
    (setq mid2 (midpt pt3 pt4)) 

    ;-- Draw the line 
    (command "line" mid1 mid2 "") 

) 



;------------------------------------------------------------------------ 
;- Function: midpt (p1 p2) 
;- Arguments: p1 is the starting point of the line 
;-    p2 is the ending point of the line 
;- 
;- Returns the midpoint of a line given two points. 
;- 
;- Copyright 2008 Jeff Winship. All rights Reserved. 
;----------------------------------------------------------------5/3/2008 
(defun midpt (p1 p2/Xavg Yavg Zavg) 

    ;-Calculate the X, Y and Z averages 
    (setq Xavg (/(+ (car p1) (car p2))2.0)) 
    (setq Yavg (/(+ (cadr p1) (cadr p2))2.0)) 
    (setq Zavg (/(+ (caddr p1) (caddr p2))2.0)) 

    ;-Return the midpoint as a list 
    (list Xavg Yavg Zavg) 
) 

Answer 1

entsel允许仅选择一个实体。如果您想要进行多项选择，则应使用ssget。

示例代码：

(setq sset(vl-catch-all-apply 'ssget (list))) 
(if (not(vl-catch-all-error-p sset)) 
    (progn 
    (setq i 0) 
    (repeat (sslength sset) 
     (setq item (ssname sset i)) 
     (print (entget item)) 
     (setq i (1+ i)) 
    );repeat 
) ; progn 
) ;if 

ssget函数是非常有用的。您可以要求用户选择实体，还可以限制用户的选择，例如，他将只能选择行或仅选择块。您也可以按照定义的标准（如图层，颜色等等）选择实体，而无需任何用户操作。

Answer 2

上一个回复不包括'ssget语句后面（列表）中的属性过滤器集。如果您需要过滤除LINE实体以外的所有内容，则需要添加一个过滤器集。