Ext动态列加载

	////////////////////////////
	  //声明grid
	var Dat;
    //表字段：ID CName EName Sex Address Mobile
    
    //声明全局变量session_Column作为当前的列集，默认是2列
   var session_column = "pno,pname,pnum,";
    //封装grid
    function DataGrid(){
        //默认2列
        this.fields = '{name:"pno"},{name:"pname"},{name:"pnum"}';
		this.columns = '{header:"组合",dataIndex:"pno",hidden:false,sortable:true},'
			 			+'{header:"名称",dataIndex:"pname",sortable:true},'
	           	 +'{header:"市值",dataIndex:"pnum",sortable:true}';
        //动态增加列
        this.addField=function(name,caption)
        {
            if(this.fields.length > 0){
                this.fields += ',';
            }
            if(this.columns.length > 0){
                this.columns += ',';
            } 
            this.fields += '{name:"' + name + '"}';
            this.columns += '{header:"' + caption + '",dataIndex:"' + name + '",sortable:true}';
        };
        //动态删除列
        this.removeField=function(name,caption)
        {
            if(this.fields.length > 0&&this.columns.length > 0)
            {                
                var d_field = ',{name:"' + name + '"}';
                var index = this.fields.indexOf(d_field);
                if(index>=0)
                {
                   this.fields = this.fields.replace(d_field,"");
                }                
                var d_column = ',{header:"' + caption + '",dataIndex:"' + name + '",sortable:true}';
                var index2 = this.columns.indexOf(d_column);
                if(index2>=0)
                {                
                    this.columns =  this.columns.replace(d_column,"");  
                }
            }
        };
        //绑定存储器
        this.ds = new Ext.data.Store
        ({	autoLoad :false,
             proxy:new Ext.data.HttpProxy({url:"griddata.action"}),
             reader:new Ext.data.JsonReader({totalProperty:"results",root:"items"}, Ext.data.Record.create(eval('(['+this.fields+'])')))
        });
      //清空字段，恢复初始值
		   this.clearFields= function(){
		       this.fields = '{name:"pno"},{name:"pname"},{name:"pnum"}';
				     this.columns = '{header:"组合",dataIndex:"pno",hidden:false,sortable:true},' +
				                 '{header:"名称",dataIndex:"pname",sortable:true},'
				                 +'{header:"市值",dataIndex:"pnum",sortable:true}';
		   };
        //实现动态增加或者删除列  
        this.RefreshDataSource = function(u){//动态添加列
            var cm1 = eval('([' + this.columns + '])');
            //默认可以对字段排序
            cm1.defaultSortable = true;
            //重新绑定数据集
            var newStore = new Ext.data.Store
            ({		autoLoad :false,
                    proxy:new Ext.data.HttpProxy({url: u}),
                    reader:new Ext.data.JsonReader({totalProperty:"results",root:"items",id :"id"},Ext.data.Record.create(eval('([' + this.fields + '])')))
            }); 
            //重新绑定grid
            this.grid.reconfigure(newStore, new Ext.grid.ColumnModel(cm1));
            //重新绑定分页工具栏
            this.pagingBar.bind(newStore);
            //重新加载数据集
            newStore.load({params:{start:0,limit:10}}); 
        }
        
        this.ds.load();
        this.pagingBar = new Ext.PagingToolbar
        ({
            displayInfo:true,
            emptyMsg:"没有数据显示",
            displayMsg:"显示从{0}条数据到{1}条数据，共{2}条数据",
            store:this.ds,
            pageSize:10
        });
        
        this.grid = new Ext.grid.GridPanel
        ({
            cm:new Ext.grid.ColumnModel(eval('([' + this.columns + '])')),
            store:this.ds,
            id:"pgrid",
            title:"组合信息", 
            loadMask:true,           
            layout:"fit",          
            autoWidth:true,
            stripeRows :true,
            frame :false,
            viewConfig : {
				autoFill :true,
				enableRowBody :true
			},
           // autoHeight:false,
          	height:440,
            autoScroll:true,           
            bbar:this.pagingBar,
            listeners:{
				  'cellclick':function(grid,rowIndex,columnIndex,e){
				  		var record = grid.getStore().getAt(rowIndex);
				  		Ext.getCmp('text1').setValue(rowIndex);
		      		}
			},
            renderTo:grid1
        });  
    }
    //动态增加列
    function AddColumn(columnName,caption){
        if(session_column.indexOf(columnName)>0)
        {
           // Ext.Msg.alert("友好提示","["+caption+"]字段已经添加过了，不能够重复！当然你想重复，要改源代码哦！");
            return;
        }
        session_column +=columnName;
        Dat.addField(columnName,caption);
    }
    //刷新页面恢复初始加载状态
    function Refresh(){
          var url = "griddata.action";
          Dat.clearFields();//清空字段，恢复初始值
          session_column = "pno,pname,pnum,";
          //Dat.RefreshDataSource(url);
    }
    
   Dat = new DataGrid();

/////调用发出请求
AddColumn("tmgamma","伽玛(T-M三因素)");
		  	url = "griddata.action?type=4&begin="+begin+"&end="+end+"&pno="+pno;
		    Dat.RefreshDataSource(url);
</script>