Extjs获取不到后台回传的json数据
前台Extjs代码:

Ext.onReady(function () {

            var store = new Ext.data.Store({
                proxy: new Ext.data.HttpProxy({ url: "/WebService/test/tb_data.ashx" }),
                reader: new Ext.data.JsonReader({
                    totalProperty: "results",
                    root: "jsonObjs"
                },
                                 [
                                   { name: 'user_name' },
                                   { name: 'user_id' },
                                   { name: 'ssyj' }
                                 ]
                           ),
                listeners: {
                    load: function () {
                        alert(store.getCount());
                    }
                }
            });

            store.load();

        });

后台代码:

public void ProcessRequest(HttpContext context)
        {
            context.Request.ContentEncoding = Encoding.GetEncoding("UTF-8");

            context.Response.ContentEncoding = Encoding.GetEncoding("UTF-8");

            context.Response.Charset = "UTF-8";

            context.Response.ContentType = "text/plain";

&