C# – Reading settings from app.config or web.config in .NET


I'm working on a C# class library that needs to be able to read settings from the web.config or app.config file (depending on whether the DLL is referenced from an ASP.NET web application or a Windows Forms application).

I've found that


works, but that code has been marked as deprecated by Microsoft.

I've read that I should be using:


However, the System.Configuration.ConfigurationManager class doesn't seem to be available from a C# Class Library project.

What is the best way to do this?

Best Solution

For a sample app.config file like below:

<?xml version="1.0" encoding="utf-8" ?>
    <add key="countoffiles" value="7" />
    <add key="logfilelocation" value="abc.txt" />

You read the above application settings using the code shown below:

using System.Configuration;

You may also need to also add a reference to System.Configuration in your project if there isn't one already. You can then access the values like so:

string configvalue1 = ConfigurationManager.AppSettings["countoffiles"];
string configvalue2 = ConfigurationManager.AppSettings["logfilelocation"];