Is it possible to add Dynamically AppSetting Key / value pair's in webconfig file?

if yes,

How? anybody can explain! through C# Coding

Thanks in advance

Balakrishnan 

here is similar thread

http://forums.asp.net/thread/1525755.aspx

hi Balakrishnan,

i'm not sure if you can modify your web.config via code or not but be aware if you change it then your web app will be surely restarted, causing users to loose session.

thanks,

satish.

Yes, you can. In ASP.NET 1.X you have to use file I/O or XML API to modify the web.config file directly. In .NET 2.0. the ConfigurationManager(for ASP.NET you should use WebConfigurationManager class) class provide methods to modify and update application's config file.

http://msdn2.microsoft.com/en-us/library/system.web.configuration.webconfigurationmanager.aspx 

However, you should take care that whenever ASP.NET application's web.config file get changed, it will restart. I don't think this should happen very frequent for an server-side application.

Hope this helps.