Using ConfigurationManager to load config from an arbitrary location

Question

I'm developing a data access component that will be used in a website that contains a mix of classic ASP and ASP.NET pages, and need a good way to manage its configuration settings.

I'd like to use a custom ConfigurationSection, and for the ASP.NET pages this works great. But when the component is called via COM interop from a classic ASP page, the component isn't running in the context of an ASP.NET request and therefore has no knowledge of web.config.

Is there a way to tell the ConfigurationManager to just load the configuration from an arbitrary path (e.g. ..\web.config if my assembly is in the /bin folder)? If there is then I'm thinking my component can fall back to that if the default ConfigurationManager.GetSection returns null for my custom section.

Any other approaches to this would be welcome!

user_227 · Answer

Try this:

System.Configuration.ConfigurationFileMap fileMap = new ConfigurationFileMap(strConfigPath); //Path to your config file
System.Configuration.Configuration configuration = System.Configuration.ConfigurationManager.OpenMappedMachineConfiguration(fileMap);

user_665783 · Answer

The accepted answer is wrong!!

It throws the following exception on accessing the AppSettings property:

Unable to cast object of type 'System.Configuration.DefaultSection' to type 'System.Configuration.AppSettingsSection'.

Here is the correct solution:

System.Configuration.ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = "YourFilePath";
System.Configuration.Configuration configuration = System.Configuration.ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);

user_507 · Answer

In addition to Ishmaeel's answer, the method OpenMappedMachineConfiguration() will always return a Configuration object. So to check to see if it loaded you should check the HasFile property where true means it came from a file.

user_5775048 · Answer

This should do the trick :

AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", "newAppConfig.config);

Source : https://www.codeproject.com/Articles/616065/Why-Where-and-How-of-NET-Configuration-Files

Using ConfigurationManager to load config from an arbitrary location

9 Answers