[求助]用鼠标选择对象的问题

sencewm

依然是菜鸟求助
我用UIStyler建立了一个按钮，那如何实现：点击该按钮后可以用鼠标选择一曲线，然后获得它的中点，我的程序如下，但是似乎总是死循环。
int GP_action_0_act_cb ( int dialog_id,
' V* D5 \4 i6 e) v             void * client_data,
             UF_STYLER_item_value_type_p_t callback_data)
: _- q+ ?4 H% K0 p6 y2 Q( y{
2 a' s- s. l( u# h! j- [     /* Make sure User Function is available. */  
( L' Z3 V3 d0 E% {7 _     if ( UF_initialize() != 0)
3 P7 X5 S1 M" w; O. W  q          return ( UF_UI_CB_CONTINUE_DIALOG );

     /* ---- Enter your callback code here ----- */
char message[133];
- v, X: B8 [1 C" U1 Qmessage[0]='\0';
strcpy(message, "请选择一条曲线");
UF_UI_selection_options_t opts;
UF_UI_mask_t mask;
int response;
$ i% }: e8 O* ?8 w; Wtag_t object, view;
double cursor[3];
' [2 Y# G4 J  A! h8 h, eint unhighlight=0;

7 U- J% r3 |  G
# Z8 q3 N# F/ F2 z! w
0 p: ^; C) G' A2 _UF_initialize();
$ H5 g" E) I7 n+ R* N2 Z4 O/ eopts.other_options=0;
opts.reserved=NULL;
& C7 g7 [4 i; G2 J3 {opts.num_mask_triples=1;
, j3 J1 l- A3 v8 P6 p1 Yopts.mask_triples=&mask;

opts.mask_triples->object_type=UF_spline_type;
opts.mask_triples->object_subtype=0;
* c% b7 O0 o( {+ i0 Uopts.mask_triples->solid_type=0;
# a7 S2 a8 m; L! \; J3 ?
1 A6 D% h& X  u; y& ~opts.scope=UF_UI_SEL_SCOPE_ANY_IN_ASSEMBLY;
" B& G* @8 \: U  ]0 J  }8 W8 ~9 kdouble port[3];
% o% q3 V! _2 z% I- w) p
. G- g- T, w% q4 f; p
do{int irc=UF_UI_select_single(message, &opts, &response, &object, cursor, &view);}

9 z* i# P+ Y1 W, A( [6 Ywhile (!(response==UF_UI_OBJECT_SELECTED));
4 T# f* d9 C/ C# u5 qif (response!=UF_UI_OBJECT_SELECTED)
{
: W' n' K3 ?; K6 J( ?/ L6 _uc1601("No Curve Selected",1);
' d# E. i% i8 `& c1 sUF_terminate ();
; |$ v0 C& X. l5 ^$ m) xreturn (UF_UI_CB_CONTINUE_DIALOG);
( y4 ~3 e) S. p: \( ]}       
  

1 v9 d$ l6 @) v. ]int ret=UF_MODL_ask_curve_props(object,0.5,port,NULL,NULL,NULL,NULL,NULL);
  char message2[133];
" d) `5 s  E+ k" e. `" A8 e/ ?  message2[0]='\0';
  sprintf (message2, "曲线中点坐标为：%f,%f,%f",port[0],port[1],port[2]);
3 v' b) ^% u; M' |  uc1601(message2,1);
/ f3 ^% U9 x2 F% B/ s2 w- H& m


UF_terminate ();
2 W" N5 ~  _* B4 \- [  |$ |return (UF_UI_CB_CONTINUE_DIALOG);
   }