Ext.define("comboxDataModel", {
        extend: "Ext.data.Model",
        fields: ["UserName", "ID"]
    });
    var testStore = new Ext.data.JsonStore({
        storeId: "testStore",
        model: "comboxDataModel",
        proxy: {
            type: "ajax",
            url: "/StoreTest/FindAllUser",
            reader: {
                type: "json",
                root: "listRoot"
            }
        }

    });

    var textCombox = new Ext.form.field.ComboBox({
        id: "testCombox",
        name: "testCombox",
        fieldLabel: "测试",
        store: testStore,
        valueField: "ID",
        displayField: "UserName",
        loadingText: "加载中...",
        listConfig: {
            loadingText: "loading..."
        },
        queryMode: "remote",
        renderTo: "test",
        listeners: {
            expand: function () {
                alert(123);
            }
        }

    });