ExtJS Combo Assignment Default value

1. The wrong example

sexCombo.on("afterrender", function() {

     sexCombo.setValue(sexStore.getAt(0).data.code); });I don't know if it's possible in some cases, but my combo store is so assigned

   <summary>///        View drop-down list of scopes///</summary>//        <returns></returns>        Public  Jsonresult getscanscopelist ()        {            list<scanscope> scopelst = new List<scanscope> {new ScanScope {Id = 0, Scanscope = "Not Completed"}, new Scanscope {id = 1, scanscope = "Completed"}, new Scanscope {id = 2, Scanscope = "All"}};            Return Json (Scopelst, jsonrequestbehavior.allowget);        }        <summary>///        View drop-down box DataSet entity////        </summary> public        class Scanscope        {            public int Id;            public string scanscope;        }

In this case, if you do not first manually use the combo dropdown to select one, the Combo.getvalue () is "" "or RawValue, My is" "and" not completed. "

2. The right approach:

var Displayfield = Thisobj.down (' Displayfield ');        var combo = Thisobj.down (' combobox[name=selectscanscope] ');        var scanstore = Combo.getstore ();        Scanstore.on (' Load ', function () {combo.setvalue (This.getat (0). Get (' Id ')); });
As for these statements, because my combo on the Tbar, I wrote in the Tbar BeforeRender event.