Saving application config data under Vista

Part 1: this part, where to save application config data
Part 2: how to save config data in an XML file using XmlDocument
Part 3: how to load (parse) XML-based config data using XmlDocument

I was a bit frustrated at finding this info on the net. It required a bunch of searches to pull it all together. I finally got what I needed, but, you know, bitch/moan/whine and all that. So here's everything in one place!

I'm assuming you're coding in C# (or at least can read it), and using .NET. And, like, Windows? Yeah.

So, part 1 of a 3-part series: where do I put my config data?

In the olden days (ie, under XP), you could just create a "config.ini" file in the current directory, ie with no path info, and it would save it in the same location that your application's exe was located. Under Vista and User Access Control (UAC), applications by default do not have write access to the Program Files folder. Plus, that folder might not be on the C: drive, and it might not be called "Program Files". So where do you save stuff now?

The correct location is in the AppData folder for the current user -- or, if you don't want to store user-specific data, in the common AppData folder. You can get these paths using the following code:

string userAppData = Environment.GetFolderPath(
Environment.SpecialFolder.ApplicationData);
string commonAppData = Envrionment.GetFolderPath(
Environment.SpecialFolder.CommonApplicationData);

You can also hunt for the environment variable %AppData% if you want. The above is .NET friendly, so it's what I used.

I encapsulated the above into a function, which I use a couple places in my config save/load code:

private static string GetConfigPath()
{
string appData = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
string myAppData = appData + "/MyAppName";
return myAppData;
}

Loading it requires the following:

string myAppFile = GetConfigPath() + "/" + kConfigFile;
if (!File.Exists(myAppFile))
return;
XmlDocument doc = new XmlDocument();
doc.Load(myAppFile);
// insert parsing here, see part 3

and saving it requires just a bit more work:

public void SaveData()
{
XmlDocument doc = CreateSaveDoc();
string myAppPath = GetConfigPath();
string myAppFile = myAppPath + "/" + kConfigFile;
if (!File.Exists(myAppFile))
{
Directory.CreateDirectory(myAppPath);
}
doc.Save(myAppFile);
}

In part 2, I cover storing data in an XmlDocument, and in part 3 I cover parsing data back out of an XmlDocument and into some local format.

(Apologies for the poor code formatting. Me and Blogger don't get along.)