.NET Class Library Get Configuration File

A class library is used by different kind of applications, like a test console, a WinForm or Web applications. And the class library needs to read a configuration file at run time. How to do that? The common way is copy the configuration file to the folder where the class library assembly is sitting. Then the configuration file can be located by reflection at run time. But this doesn't work in ASP.NET web site environment because of the .NET dynamic compilation process. One resolution is to handle the path differently in web environment. Let's say if We have a convention of copying the configuration file to the root folder of web site, then the code to retrieve the full path of configuration file is like:

    public static string GetConfigurationFile(string fileName)
    {
        string asmLocation = Assembly.GetExecutingAssembly().Location;
        string asmFolder = asmLocation.Substring(0, asmLocation.LastIndexOf(@"\"));
        string fileFullPath = asmFolder + @"\" + fileName;

        // Fix the temporary folder issue when running in web environment
        if (fileFullPath.Contains(@"\Microsoft.NET\Framework"))
        {
            fileFullPath = System.Web.Hosting.HostingEnvironment.MapPath("/") + fileName;
        }

        return fileFullPath;
    }

(Updated 2008/2) Another easy way to get configuration file is using AppDomain.CurrentDomain.SetupInformation.ConfigurationFile property which maps to app.config for Cosole/WinForm applications, and maps to web.config in ASP.NET.