new Ext.data.JsonStore({
                    // store configs
                    autoDestroy: true,
                    storeId: 'store',
                    // reader configs
                    idProperty: 'id',
                    fields: ['id', 'title']

                });

                Ext.Ajax.request({
                    url: 'WebForm1.aspx',
                    success: function (response, options) {
                        var storeJson = Ext.decode(response.responseText);
                        store.loadData(storeJson);
                    }
                });

                // Grid
                var grid = new Ext.grid.GridPanel({
                    renderTo: document.body,
                    title: 'Move Database',
                    height: 200,
                    width: 500,
                    store: store,
                    columns: [
                        { header: "Id", dataIndex: 'id' },
                        { header: "Title", dataIndex: 'title' }
                        ]
                });
            }); 
     </script>

class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            User user = new User();

            user.success = true;
            user.id = 1;
            user.title = "title";

            //JavaScriptSerializer类在System.Web.Extensions.dll中，注意添加这个引用  
            JavaScriptSerializer serializer = new JavaScriptSerializer();

            //JSON序列化  
            string result = serializer.Serialize(user);

            Response.Write(result);
        }
    }
    public class User
    {
        private bool _success;

        public bool success
        {
            get { return _success; }
            set { _success = value; }
        }

        private int _id;

        public int id
        {
            get { return _id; }
            set { _id = value; }
        }

        private string _title;

        public string title
        {
            get { return _title; }
            set { _title = value; }
        }

    }