改变下拉编辑框的宽度

{$externalsym cb_geteditsel}
  cb_geteditsel            = $0140;
  {$externalsym cb_limittext}
  cb_limittext             = $0141;
  {$externalsym cb_seteditsel}
  cb_seteditsel            = $0142;
  {$externalsym cb_addstring}
  cb_addstring             = $0143;
  {$externalsym cb_deletestring}
  cb_deletestring          = $0144;
  {$externalsym cb_dir}
  cb_dir                   = $0145;
  {$externalsym cb_getcount}
  cb_getcount              = $0146;
  {$externalsym cb_getcursel}
  cb_getcursel             = $0147;
  {$externalsym cb_getlbtext}
  cb_getlbtext             = $0148;
  {$externalsym cb_getlbtextlen}
  cb_getlbtextlen          = $0149;
  {$externalsym cb_insertstring}
  cb_insertstring          = $014a;
  {$externalsym cb_resetcontent}
  cb_resetcontent          = $014b;
  {$externalsym cb_findstring}
  cb_findstring            = $014c;
  {$externalsym cb_selectstring}
  cb_selectstring          = $014d;
  {$externalsym cb_setcursel}
  cb_setcursel             = $014e;
  {$externalsym cb_showdropdown}
  cb_showdropdown          = $014f;
  {$externalsym cb_getitemdata}
  cb_getitemdata           = $0150;
  {$externalsym cb_setitemdata}
  cb_setitemdata           = $0151;
  {$externalsym cb_getdroppedcontrolrect}
  cb_getdroppedcontrolrect = $0152;
  {$externalsym cb_setitemheight}
  cb_setitemheight         = $0153;
  {$externalsym cb_getitemheight}
  cb_getitemheight         = $0154;
  {$externalsym cb_setextendedui}
  cb_setextendedui         = $0155;
  {$externalsym cb_getextendedui}
  cb_getextendedui         = $0156;
  {$externalsym cb_getdroppedstate}
  cb_getdroppedstate       = $0157;
  {$externalsym cb_findstringexact}
  cb_findstringexact       = $0158;
  {$externalsym cb_setlocale}
  cb_setlocale             = 345;
  {$externalsym cb_getlocale}
  cb_getlocale             = 346;
  {$externalsym cb_gettopindex}
  cb_gettopindex           = 347;
  {$externalsym cb_settopindex}
  cb_settopindex           = 348;
  {$externalsym cb_gethorizontalextent}
  cb_gethorizontalextent   = 349;
  {$externalsym cb_sethorizontalextent}
  cb_sethorizontalextent   = 350;
  {$externalsym cb_getdroppedwidth}
  cb_getdroppedwidth       = 351;
  {$externalsym cb_setdroppedwidth}
  cb_setdroppedwidth       = 352;
  {$externalsym cb_initstorage}
  cb_initstorage           = 353;
  {$externalsym cb_msgmax}
  cb_msgmax                = 354;