1. 检查数据库要花多少时间才能返回数据.

2. 设置Web响应的长度(您可以使用来在web.config中调整JSON响应的大小.)

1. check how much time your database is taking to returning data.

2. Set length of web response ( You can adjust the JSON response size in the web.config with ).

<configuration>
<system.web.extensions>
    <scripting>  
         <webServices>                                                   
             <jsonSerialization maxJsonLength="1000000" />                 
         </webServices>
    </scripting>
</system.web.extensions>
</configuration>