How to pass value in app.config

[rupinder03]

I m passing following connection string in app.config file

<appSettings>
<add key="ConnectionString" value=""/>
</appSettings>

I made a one form by which user create his own database......... and connection string is qutomatically created with dat database.........nd i hv to pass dat connection string into appsettings of aap.config file where value is blank......nd when next time user start this application.....He should connect with dat database which he created.....this is window application

plz reply
Thanks

[kenobewan]

Assume its similar to web configurationmanager.appsettings["connstring"]. HTH.