Edit connectionstring of Web.config in webservice (ASPNET)

I'm using webservice for my Desktop application(C#). I want to edit my database connectionstring programmatically in web.config(in web service) through C#. How to do this? Any s开发者_开发问答imple idea?

ConfigurationManager.ConnectionStrings["connName"].ConnectionString = "new connectionstring";

Take a look at WebConfigurationManager.