Extjs Grid checkbox selected based on data initialization __js

Background: Depending on the business requirements, you need to load a lot of data into the grid, and then determine whether the data is selected based on one of the properties of each piece of data.

Process: Google a bit, found a foreigner to provide the following method.

Ext.Ajax.request ({method: ' POST ', url: ' index.php/mapper/get_tag_subfields/', Scope:this, Params: {Id:this.gridB.getSelectionModel (). GetSelection () [0].data.id,}, Success:function (XHR) {var json =ext.decode (Xhr.responsetext);//Make sure to decode for loaddata to work//data is formatted, JU
            St Needto Load Data storemappersubfields.loaddata (json.data);
                    Mark Checkboxes if (json.data.length) {for (var i = 0; I <json.data.length; i++) { var rec =this.gridc.store.getbyid (json.data[i].id);
                       Json.data[i].getid () if (Rec.data.field_type = =//Select all records have have ' s ')
                    This.gridC.getSelectionModel (). Select (Rec,true,false);
            }}}, Failure:function () {ext.getbody (). unmask (); Alert (' AJAX Failure:unabLeto process call ');
}
    }); }, this);

Source Document

But when I use the Red line part of the error. Say Views[0] can't find it.

Here's My Code:

 Ext.Ajax.request ({url: '/aaaaaaaaaaa/bbbbbbbbbbbbbbb.do ', Method: ' Post ', para  
			        MS: {methodname: ' aaaaaaaaaaa ', Policyid:policyid, appid:appid},
			            Success:function (response, options) {var result = Ext.JSON.decode (Response.responsetext);
				        VAR edittitle= ' acquisition strategy ' +policyname+ ' Operation request modification ';
				                var editpolicypanelopers = new PM.view.policy.PolicyEditOpers ({title:edittitle//,
				        Data:result.data}); Set PolicyId Ext.ComponentQuery.query (' window#policyeditopers textfield#selectpolicyid ') [0].setvalue (PolicyId)
				        ;
				        Ext.ComponentQuery.query (' window#policyeditopers textfield#selectappid ') [0].setvalue (AppID);
				        var Opergrid = Ext.ComponentQuery.query (' window#policyeditopers grid#oper_grid ') [0];
var opersstore = Ext.getstore (' Businessoperstore ');				        if ("Undefined"!= typeof Opersstore) {opersstore.loaddata (result.data);
				            Opergrid.reconfigure (Opersstore); for (var i = 0; i < result.data.length i++) {var rec = operGrid.store.getById (result.data[i].bu Sinessoperid);
			                    	Json.data[i].getid () if (rec.data.selected = = true) {//Select all records have have ' s '
			                    Opergrid.getselectionmodel (). Select (Rec,true,false);
			        }}//Set AppID editpolicypanelopers.show ();  
			           }, Failure:function () {var o = Ext.JSON.decode (response.responsetext); 
			             alert (o.msg);
			        Ext.Msg.alert (' Cue message ', o.message);  }  
			    });

Consulted the method of select (Rec,true,false). Say rec This parameter is either index or an instance of the record.
Asked at the same time, he said it was a matter of rendering. Say I'm calling the wrong place.
And then there's your own mess: Check the source code and find the property selected private. It cannot be set to be checked or not.
After a few hours, I thought of my colleague's words.
Finally, I patiently went to practice. Sure enough, that's the problem. The problem was solved, but it took a whole afternoon plus one night.

Here is the code fragment:

Init:function () {
		This.control ({
			  ' policyeditopers Grid#oper_grid ': {
				  Afterrender:this.selectModel }}
	,
	selectmodel:function () {
		Ext.Msg.alert (' Selectmodel ', ' Test ')
		 ; var Opergrid = Ext.ComponentQuery.query (' window#policyeditopers grid#oper_grid ') [0];
		for (var i = 0; i < Opergrid.getselectionmodel (). Store.data.items.length i++) {
            var rec = operGrid.store.getById ( Opergrid.getselectionmodel (). Store.data.items[i].data.businessoperid); Json.data[i].getid ()
            if (rec.data.selected = = true) {//Select all records have have ' s '
            	opergrid.getselecti Onmodel (). Select (Rec,true,false);}}}