code: function () {
              var me = this, shortcutkeys = this.shortcutkeys;
              me.addListener('keydown', function (type, e) {
                  var keyCode = e.keyCode || e.which;
                  for (var i in shortcutkeys) {
                      var tmp = shortcutkeys[i].split(',');
                      for (var t = 0, ti; ti = tmp[t++];) {
                          ti = ti.split(':');
                          var key = ti[0], param = ti[1];
                          if (/^(ctrl)(\+shift)?\+(\d+)$/.test(key.toLowerCase()) || /^(\d+)$/.test(key)) {
                              if (( (RegExp.$1 == 'ctrl' ? (e.ctrlKey || e.metaKey) : 0)
                                  && (RegExp.$2 != "" ? e[RegExp.$2.slice(1) + "Key"] : 1)
                                  && keyCode == RegExp.$3
                                  ) ||
                                  keyCode == RegExp.$1
                                  ) {
                                  if (me.queryCommandState(i,param) != -1)
                                      me.execCommand(i, param);
                                  domUtils.preventDefault(e);
                              }
                          }
                      }
  
                  }
              });
          }
docs: 对编辑器设置keydown事件监听，绑定快捷键和命令，当快捷键组合触发成功，会响应对应的命令
  @method _bindshortcutKeys
  @private