Reading settings from app.config or web.config in .NET

Question

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

ConfigurationSettings.AppSettings.Get("MySetting") 

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

I've read that I should be using:

ConfigurationManager.AppSettings["MySetting"] 

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?

Answer 1

You'll need to add a reference to System.Configuration in your project's references folder.

You should definitely be using the ConfigurationManager over the obsolete ConfigurationSettings.

Answer 2

For a sample app.config file like below:

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

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"];