Easyui datagrid 绑定键盘上下键操作选中行的问题

Question

描述：主界面打开一个windows，windwos里面包含一个datagrid，欲用键盘上下键控制上下选择行:
1、
datagrid是在一个easyui-window中的，打开windows（包含datagrid）：  
$('#win').window('open');
为了用上下键可以向上向下选中行,绑定扩展方法
$('#detail').datagrid('keyCtr');//
//扩展的方法
$.extend($.fn.datagrid.methods, {
    keyCtr: function (jq) {
        return jq.each(function () {
            var grid = $(this);
            grid.datagrid('getPanel').panel('panel').attr('tabindex', 1).bind('keydown', function (e) {
                switch (e.keyCode) {
                    case 38: // up
                        var selected = grid.datagrid('getSelected');                        
                        var rows = grid.datagrid('getRows');
                        if (selected) {
                            var index = grid.datagrid('getRowIndex', selected);
                            if (index > 0) {
                                grid.datagrid('selectRow', index - 1);//???
                            }
                        } else {
                            grid.datagrid('selectRow', rows.length - 1);
                        }
                        break;
                    case 40: // down
                        var selected = grid.datagrid('getSelected');
                        if (selected) {
                            var index = grid.datagrid('getRowIndex', selected);
                            if (index < grid.datagrid('getRows').length - 1) {
                                grid.datagrid('selectRow', index + 1);//???
                            }
                        } else {
                            grid.datagrid('selectRow', 0);
                        }
                        break;                }
            });
        });
    }
});
问题：
   主界面第一次打开windows，用上下键可以正常的跳到上一行、下一行；
   关闭windows  [$('#win').window('open');] 后再打开，再点↓键，则是跳了两行，就像是index+2 了；
   再关闭，重新打开，就是index+3了；......为什么呢？
窗体的关闭的确不是销毁，里面的东西还在，但是我每次都是重新取的选中行啊 var selected = grid.datagrid('getSelected'); 

Answer 1

多加一个公共变量就好了。var isbind=false;
//扩展的方法
$.extend($.fn.datagrid.methods, {
    keyCtr: function (jq) {
        return jq.each(function () {
            var grid = $(this);
            if(!isbind){
            grid.datagrid('getPanel').panel('panel').attr('tabindex', 1).bind('keydown', function (e) {
                switch (e.keyCode) {
                    case 38: // up
                        var selected = grid.datagrid('getSelected');                        
                        var rows = grid.datagrid('getRows');
                        if (selected) {
                            var index = grid.datagrid('getRowIndex', selected);
                            if (index > 0) {
                                <span style="color: #FF0000;">grid.datagrid('selectRow', index - 1);//???</span>
                            }
                        } else {
                            grid.datagrid('selectRow', rows.length - 1);
                        }
                        break;
                    case 40: // down
                        var selected = grid.datagrid('getSelected');
                        if (selected) {
                            var index = grid.datagrid('getRowIndex', selected);
                            if (index < grid.datagrid('getRows').length - 1) {
                                <span style="color: #FF0000;">grid.datagrid('selectRow', index + 1);//???</span>
                            }
                        } else {
                            grid.datagrid('selectRow', 0);
                        }
                        break;
 
                }
            });
          isbind=true;
          }
        });
    }
});