扩展GridPanel,附带分页选中状态，实现快速构建一个功能齐全的Grid

使用简单的配置就可以实现　store, columns, selModel , pagingToolbar , 

最重要的一点是实现分页时可以保持前一页的选中状态， 
　但是要遵守其中的一些规定，至于哪些规定呢，看下面的代码就知道啦！ 
　代码如下： 

/*
 * @class Ext.ux.grid.CollectGrid
 * @version: 1.0
 * @author: chengbao_zhu
 *
 * Example : Ext.onReady(function(){
              var CM_JR_Record = [
              {
                 dataIndex:"", //the ColumnModel options alse the JsonReader mapping (required)
                 header:"",    //the ColumnModel options (required)
                 visiable: false, //my expands option to show the header or not (options)
                 type: date,   //the type of this data (options)
                 ...another options of ColumnModel
              },{
                 dataIndex : '',
                 header : "",
                 width : 130
              }];

              var myGrid = new Ext.ux.grid.CollectGrid({
                  url : 'MyJsp.jsp',          // the store load url (required)
                  CM_JR_Record: CM_JR_Record, //.....(required)
                  rowNumber:true,             //true to add a Ext.grid.RowNumberer,defalut(true)
                  checkBox:true,              //true to add a Ext.grid.CheckBoxSelectionModel,default(true)
                  pagingBar:true,             //true to add a Ext.PagingToolBar,default(true)
                  pagingConfig:objcet,        //config pagingToolBar if pagingBar is true
                  keepSelectedOnPaging: true, //true to FireEvent when you paging to keep the state of record selected
                  recordIds : new Array() ,   // store seleced ids when keepSelectedOnPaging is true
                  idColName :'stat_id',       //the id column name

                  ...another
                  width : 700,
                  height: 600,

                  title : 'This is My Grid'  ,
                  renderTo: 'my_grid'
              });

              myGrid.store.load({params:{start:0,limit:myGrid.pagingConfig.pageSize}});
              //myUxGrid.render();
              myGrid.on('rowclick',function(grid,rowIndex,e){
                alert(grid.getStore().getAt(rowIndex).data['stat_id']);
              }
              );
         }
         );
 */


Ext.namespace('Ext.ux.grid');

Ext.ux.grid.CollectGrid = Ext.extend(Ext.grid.GridPanel,{

    /*
     * true to keep the records selected when you paging
     * @default(false)
     * @type: boolean
     */
    keepSelectedOnPaging: false,

    /*
     * the array to store the record id
     * @type: array
     */
    recordIds:new Array(),

    /*
     * set your id Column Name
     * @default : this.CM_JR_Record[0].dataIndex
     */
    idColName:'',

    /*
     * set this.store.load url;
     * @type: string
     */
    url: '',

    /*
     * show the rowNumber or not
     * @type: boolean
     * @default: true
     */
    rowNumber : true,

    /*
     * set the grid sm,if checkBoxSelection=true,sm=CheckBoxSelectionModel
     * else sm=RowSelectionModel,default to true;
     * @type: boolean
     */
    checkBox: true,

    /*
     * set the grid cm array;
     * set the JsonReader record;
     *
     * format: [{name:'',header:'',visiable:'',...another cm options},{}],
     * @name=dataIndex
     * @visiable: set this record to the cm(grid header) default(true)
     * @type: array (records)
     */
    CM_JR_Record: null,

    /*
     * true to add a bottom paging bar
     * @defalut: true
     * @type: boolean
     */
    pagingBar: true,

    /*
     * config paging bar if pagingBar set true
     * @type: object
     * @default: {pageSize: 20,store: this.store,displayInfo: true,
     *            displayMsg: '当前记录数: {0} - {1} 总记录数: {2}',
     *            emptyMsg: '<b>0</b> 条记录'}
     */
    pagingConfig:{
        pageSize: 20,
        //store: this.store,
        displayInfo: true,
        displayMsg: '当前记录数: {0} - {1} 总记录数: {2}',
        emptyMsg: '<b>0</b> 条记录'
    },

    viewConfig:{
        forceFit: true
    },

    //private
    initComponent: function(){
        if(this.CM_JR_Record){
            this.init_SM_CM_DS();
        }
        if(this.pagingBar){
            this.init_PagingBar();
        }
        if(this.keepSelectedOnPaging){
            this.init_OnPaging();
        }
        Ext.ux.grid.CollectGrid.superclass.initComponent.call(this);
    },

    /*
     * init the grid use the config options
     * @return: void
     * @params: none
     */
    init_SM_CM_DS: function(){
        var gCm = new Array();
        var gRecord = new Array();

        if(this.rowNumber){
            gCm[gCm.length]=new Ext.grid.RowNumberer();
        }
        if(this.checkBox){
            var sm = new Ext.grid.CheckboxSelectionModel();
            gCm[gCm.length] = sm;
            this.selModel = sm;
        }

        for(var i=0;i<this.CM_JR_Record.length;i++)
        {
            var g = this.CM_JR_Record[i];
            if(g.visiable || g.visiable=='undefined' || g.visiable==null){
                gCm[gCm.length] = g;
            }

            gRecord[gRecord.length]={
                name: g.dataIndex,
                type: g.type || 'string'
            }
        }

        //create grid columnModel
        this.cm = new Ext.grid.ColumnModel(gCm);
        this.cm.defaultSortable = true;

        //create a jsonStore
        this.store = new Ext.data.Store({

            proxy: new Ext.data.HttpProxy({
                url: this.url,
                method: 'post'
            }),
            reader:new Ext.data.JsonReader({
                totalProperty: 'totalProperty',
                root: 'root'
            },
            Ext.data.Record.create(gRecord)
            )

        });


        this.pagingConfig.store = this.store;

        if(this.pagingBar){
            this.store.load({params:{start:0,limit:this.pagingConfig.pageSize}});
        }else{
            this.store.load();
        }

    },

    /*
     * 创建并初始化paging bar
     */
    init_PagingBar: function(){
        var bbar = new Ext.PagingToolbar(this.pagingConfig);
        this.bbar = bbar;
    },

    init_OnPaging: function(){

        this.idColName = this.CM_JR_Record[0].dataIndex ;//默认第一列为ID列

        this.selModel.on('rowdeselect',function(selMdl,rowIndex,rec ){


                for(var i=0;i<this.recordIds.length;i++)
                {
                    if(rec.data[this.idColName] == this.recordIds[i]){
                        this.recordIds.splice(i,1);
                        return;
                    }
                }


       },this);

       this.selModel.on('rowselect',function(selMdl,rowIndex,rec){
            if(this.hasElement(this.recordIds)){
                for(var i=0;i<this.recordIds.length;i++){
                    if(rec.data[this.idColName] == this.recordIds[i]){
                        return;
                    }
                }
            }

            this.recordIds.unshift(rec.data[this.idColName]);

       },this);

       this.store.on('load',function(st,recs){
            if(this.hasElement(this.recordIds)){
                st.each(function(rec){
                    Ext.each(this.recordIds,function(item,index,allItems){
                        if(rec.data[this.idColName] == item){
                            this.selModel.selectRecords([rec],true);
                            return false;
                        }
                    },this);
                },this);
            }
       },this);

    },

    hasElement : function(recIds){
        if(recIds.length > 0)
            return true;
        else
            return false;
    }

}
)