<appSettings>
<add key="connstring" value="provider=microsoft.jet.oledb.4.0;data source=|datadirectory|***.mdb"/>
<!--<add key="connstringdata" value="provider=microsoft.jet.oledb.4.0;data source=|datadirectory|***.mdb"/>-->
</appSettings>
原文：https://www.cnblogs.com/houweidong/p/12263276.html