初学ExtJS，各位大神求救，GridPane分页读取不到json 格式的数据

这是返回的json数据:
{totalProperty:100,root:[{id:0,name:*name0*,desc:*desc0*},{id:1,name:*name1*,desc:*desc1*},{id:2,name:*name2*,desc:*desc2*},{id:3,name:*name3*,desc:*desc3*},{id:4,name:*name4*,desc:*desc4*},{id:5,name:*name5*,desc:*desc5*},{id:6,name:*name6*,desc:*desc6*},{id:7,name:*name7*,desc:*desc7*},{id:8,name:*name8*,desc:*desc8*},{id:9,name:*name9*,desc:*desc9*}]}