ConfigurationManager reading wrong file - Web.config instead of App.config

Question

I was working on ASP.NET MVC project and decided to extract some functionality to a separate class library project (in the same solution).

I moved some of the elements in <appSettings></appSettings> from Web.config in main project (let's call it project A) to App.config in class library project (let's call it project B). I added a reference to System.Configuration.dll to access the ConfigurationManager in project B.

Sample App.config file is for project B is below.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="Key1" value="Value1"/>
    <add key="Key2" value="Value2"/>
  </appSettings>
</configuration>

I access these settings as follows (in project B).

string key1 = ConfigurationManager.AppSettings["Key1"];
string key2 = ConfigurationManager.AppSettings["Key2"];

I noticed that the values for key1 and key2 returned by ConfigurationManager are null.

When debugging I see that ConfigurationManager pull values from the original Web.config in project A (the other entires in <appsettings></appsettings> section that I did not move to project B)!

This does not make any sense to me. Could someone tell me what I am doing wrong, so I could access settings in App.config?

Thanks.

Web projects use web.config, not app.config. Why do you want to change the name of the configuration file? — , Sep 09 '13 at 17:18
It's a separate project that is using App.config. The main web project references this project and uses its functionality. — sakura-bloom, Sep 09 '13 at 17:20

score 8 · Accepted Answer · edited May 23 '17 at 11:46

8

App.config that resides in a Class Library project would not be loaded (at least not without extra effort), the only configuration loaded by the framework is the Client configuration (i.e the Web.config of a project that references and uses your Class Library).

See this answer for possible solutions.

edited May 23 '17 at 11:46

Community

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answered Sep 09 '13 at 17:22

haim770

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I guess in my case it is better to keep all settings in Web.config then, since it is the Client that's providing the values. Thank you for clearing this up! – sakura-bloom Sep 09 '13 at 17:29
Did you look into the possible solutions in the link? it's relatively easy to achieve – haim770 Sep 09 '13 at 17:31
You're right, it's relatively easy to do. I'll consider doing it that way. – sakura-bloom Sep 09 '13 at 17:36

ConfigurationManager reading wrong file - Web.config instead of App.config

1 Answers1