draggable datagrid columns

$.extend($.fn.datagrid.methods,{
columnMoving: function(jq){
return jq.each(function(){
var target = this;
var cells = $(this).datagrid('getPanel').find('div.datagrid-header td[field]');
cells.draggable({
revert:true,
cursor:'pointer',
edge:5,
proxy:function(source){
var p = $('<div class="tree-node-proxy tree-dnd-no" style="position:absolute;border:1px solid #ff0000"/>').appendTo('body');
p.html($(source).text());
p.hide();
return p;
},
onBeforeDrag:function(e){
e.data.startLeft = $(this).offset().left;
e.data.startTop = $(this).offset().top;
},
onStartDrag: function(){
$(this).draggable('proxy').css({
left:-10000,
top:-10000
});
},
onDrag:function(e){
$(this).draggable('proxy').show().css({
left:e.pageX+15,
top:e.pageY+15
});
return false;
}
}).droppable({
accept:'td[field]',
onDragOver:function(e,source){
$(source).draggable('proxy').removeClass('tree-dnd-no').addClass('tree-dnd-yes');
$(this).css('border-left','1px solid #ff0000');
},
onDragLeave:function(e,source){
$(source).draggable('proxy').removeClass('tree-dnd-yes').addClass('tree-dnd-no');
$(this).css('border-left',0);
},
onDrop:function(e,source){
$(this).css('border-left',0);
var fromField = $(source).attr('field');
var toField = $(this).attr('field');
setTimeout(function(){
moveField(fromField,toField);
$(target).datagrid();
$(target).datagrid('columnMoving');
},0);
}
});

// move field to another location
function moveField(from,to){
var columns = $(target).datagrid('options').columns;
var cc = columns[0];
var c = _remove(from);
if (c){
_insert(to,c);
}

function _remove(field){
for(var i=0; i<cc.length; i++){
if (cc[i].field == field){
var c = cc[i];
cc.splice(i,1);
return c;
}
}
return null;
}
function _insert(field,c){
var newcc = [];
for(var i=0; i<cc.length; i++){
if (cc[i].field == field){
newcc.push(c);
}
newcc.push(cc[i]);
}
columns[0] = newcc;
}
}
});
}
});

当dg 初始化后 ，调用此方法
 $('#tt').datagrid('columnMoving');