How to edit and save connection string in web.config file during installation in C #?

The easy way might just be to read in the web.config file and replace the line and then output the web.config again:

e.g .: in web.config containing:

...
<add name="Application" connectionString="SETUP_CONNECTION_STRING" />
...

      

        
        
        
      

    

replace SETUP_CONNECTION_STRING

with the actual line:

This assumes its initial setup, where multiple parameters can be set without the need for configuration classes, etc.