Updating AppSettings via ASP.NET MVC Controller

Question

I\'m writing a basic little forums web app (for fun and to sharpen the ole\' saw), and I\'m having a bit of trouble with AppSettings.

My plan is to have these settings i

Answer 1

Change your first line to this:

var config = WebConfigurationManager.OpenWebConfiguration("~");

Confusing as it may be, OpenWebConfiguration expects the virtual path where the Web.config resides, excluding the file name. I guess the logic is that there will only be one Web.config in any given directory so including the name is unnecessary.

The MSDN documentation ultimately clues us in here - if you look at the examples they all use explicit relative paths, and when hosting under IIS allow you to specify config files from other locations, for example:

OpenWebConfiguration("/siteName", "Default Web Site", null, "myServer");

Addendum:

So why does OpenWebConfiguration("~/Web.config") work at all? I'm not sure I can definitively explain it, but try this for kicks: change it to ("~/Foo.bar"). The same result! You can read - your same Web.config file - but cannot write! (now try adding the foo.bar directory to your site, then put a Web.config inside it...)

Since OpenWebConfiguration expects a directory (and apparently allows non-existent ones, as long as it finds a Web.config within the parent), I think this is why mistakenly specifying ~/Web.config as a "path" allows us to load the root config, but not save it.