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How to acced to my app.config from c# interactive?

I initialized the interactive element with the project from the context menu of my project.
I am testing a function in C# interactive that needs to read my app.config file to get a connectionstring.
I got the next error:
No connection string named 'ccnName' could be found in the application config file.
When I use the next code, i get a null value. I suppose it is because it is not reading the app.config of my project.
ConfigurationManager.ConnectionStrings["cnnName"]
It is the only connectionstring that the default app.config has:
[data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true]
In this post from 2012 with the same topic, one engineer involved in this project said that this option was not available. I hope it is available now in 2018
So, nowadays how can i load the app.config that i want?

"Constructor" was the magic word. This may not help in your case since you've found a solution, but it might be helpful for others in the same situation.
If you inject a System.Configuration.Configuration object into the class, you don't have to rely on ConfigurationManager's static properties.
public class LibraryClass
{
private Configuration _configuration;
public LibraryClass(Configuration configuration)
{
_configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
}
public void FunctionUnderTest()
{
string connectionString = _configuration.ConnectionStrings.ConnectionStrings["cnnName"].ConnectionString;
// Connect to the database as you normally would.
}
}
In a console/GUI application and unit tests, load it like this to use {anything}.config:
Configuration configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
// Register 'configuration' as a singleton using the container of your choice.
In a web application, load it like this to use web.config:
Configuration configuration = WebConfigurationManager.OpenWebConfiguration("~/Web.config");
// Register 'configuration' as a singleton using the container of your choice.
To use it in C# Interactive, load it using the first method and provide the dependency to the class directly:
#r "System.Configuration"
Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration(
new ExeconfigurationFileMap() { ExeConfigFilename = #"path\to\Arbitrary.config" },
ConfigurationUserLevel.None);
var lib = new LibraryClass(configuration);
lib.FunctionUnderTest();
Note that the section properties are an extra layer deep compared to what you would normally expect.
I think it has something to do with how ConfigurationManager's static properties work with the Configuration instance.

exePath must be specified when not running inside a stand alone exe

When i am using a web application, the line of code below
Configuration objConfig =
ConfigurationManager.OpenExeConfiguration( ConfigurationUserLevel.None);
in class library are giving this error:
"exePath must be specified when not running inside a stand alone exe."
Previously a console application was being used, and the code could access the app.config. I tried using the System.Web.Configuration in class library but the dll was not present in the .Net tab for "Add reference".
Kindly help :)

You need to use a different configuration manager in a web context. The following code
block shows an example of how to deal with this:
System.Configuration.Configuration configuration = null;
if (System.Web.HttpContext.Current != null)
{
configuration =
System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
}
else
{
configuration =
ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
}

I'm not sure what you're doing; but at first glance it looks like you're trying to use code written for a WinForms application in a web environment. This almost certainly will not work, since your web app won't have the permissions you need.
Try looking up how to do this in a web environment (since you seem to be dealing with config files, try searching on WEB.CONFIG to start)

I tried to use the answer from #shane but ended up with the same exception using Hangfire. This code worked for me though:
System.Configuration.Configuration configFile = null;
if (System.Web.HttpContext.Current != null)
{
configFile =
System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
}
else
{
System.Configuration.ExeConfigurationFileMap map = new ExeConfigurationFileMap { ExeConfigFilename = $"{System.AppDomain.CurrentDomain.BaseDirectory}Web.Config" };
configFile = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
}
Note that editing Web.config will cause the application pool to restart!

Whats wrong with my log4net configuration?

I have an ASP.NET MVC app which has a bootstrapper class that configures log4net during application startup as follows:
public static void Configure(IApplicationContext applicationContext)
{
var appender = new log4net.Appender.FileAppender
{
Layout = new log4net.Layout.PatternLayout("%d [%t]%-5p %c [%x] <%X{auth}> - %m%n"),
File = applicationContext.GetLogFile().FullName
};
BasicConfigurator.Configure(appender);
}
I have checked that when I call the logging function later that the repository is configured:
LogManager.GetRepository().Configured
this returns true.
The location of applicationContext.GetLogFile().FullName exists and also has permissions set for any user to be able to create and modify files, so I don't quite understand why this fails to create a log file or output any data.
Now I know you can use config files and XML in the Web.config but because the log file location and configuration will change from site to site I need to do this in code.
Please can someone help me.

you should add an
appender.ActivateOptions();

Class design/best approach for initializing a user configuration file

I want to initialize a user configuration through a user configuration file. The path for the file can be read from the registry.
The file is located in a folder with the user's name.
So I need the following functionality:
Reading a string from registry
building the path to the configuration file
Reading the file into a configuration object
Now there are several approaches to handle this:
First, I need
one "helper"-class for getting the file path (let's call it Shared)
one "container"-class for the configuration information (let's call it Configuration)
So, Shared has a function/property like UserConfigurationFile which returns the path to the configuration file.
To get the path to the file I have a function InitializeUserConfigurationFile() which is called in the constructor of Shared:
class Shared {
public Shared()
{
InitializeUserConfigurationFile();
}
void InitializeUserConfigurationFile()
{
//
// Reads username
//
//
// Reads path from Registry
//
//
// etc.
//
}
//
// etc.
//
}
Any better suggestions?
When I want to Initialize my Container I have different options:
Is it best to initialize the user configuration within the constructor?
Sth. like:
class Container
{
Shared shared = new Shared();
public Container()
{
InitializeUserConfiguration();
}
void InitializeUserConfiguration()
{
LoadConfiguration(shared.UserConfigurationFile);
}
void LoadConfiguration(string filename)
{
//
// Initializes all parameters frome filename
//
}
}
Or through two steps (through an own method LoadConfiguration())?
Sth. like:
Shared shared = new Shared();
Container container = new Container();
container.LoadConfiguration(shared.UserConfigurationFile);
Or inside the constructor of Container by delivering a filename?
Sth. like:
Shared shared = new Shared();
Container container = new Container(shared.UserConfigurationFile);
or everything in Container..?
There are so many ways...
I hope somebody knows a best-approch...
Regards,
Inno

It is better to use standard configuration classes exist in .net. Such as ApplicationSettingsBase and Configuration.
Here you can find good article series:
Unraveling the Mysteries of .NET 2.0 Configuration
Unraveling the Mysteries of .NET 2.0 Configuration
Cracking the Mysteries of .NET 2.0 Configuration

For best practices, don't use the registry, and don't reinvent the wheel.
Since you didn't mention it, have you looked at the System.Configuration namespace?
The .NET Framework constains a perfectly good configuration system that is well tested. It is also the domain of Sys Admins, who also know about config files and the accompanying tools.
So it is unclear why you are reinventing the wheel, possibly making it a little less round.
There are practical reasons to shun the Registry (distribution, backup) but also, as arbiter points out, it is not going to move to other (future) platforms. Did you notice that those namespaces are not starting with System ?

How do I specify the name of my application's App.config file in WPF?

This is very frustrating... I can set the Configuration File for a Windows Forms Application just fine. Consider this:
public static void Main(){
AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", #"SharedAppConfig.config");
//do other things
}
However, in a WPF application, this doesn't seem to work! If I set this value, the value of the AppDomain.CurrentDomain.SetupInformation.ConfigurationFile property is correct, but any calls to that configuration file while debugging yield no results. There are WCF configuration settings in an App.config that I need to share between application, so this is my proposed solution. Is it possible to dynamically set the location of my config file in WPF?
Help! Thanks!

You should be able to do something along the lines of:
using System.Configuration;
public class TryThis
{
Configuration config = ConfigurationManager.OpenExeConfiguration("C:\PathTo\app.exe");
public static void Main()
{
// Get something from the config to test.
string test = config.AppSettings.Settings["TestSetting"].Value;
// Set a value in the config file.
config.AppSettings.Settings["TestSetting"].Value = test;
// Save the changes to disk.
config.Save(ConfigurationSaveMode.Modified);
}
}
NOTE: This will attempt to open a file named app.exe.config at C:\PathTo. This also REQUIRES that a file exists at the same path with the name "app.exe". The "app.exe" file can just be an empty file though. For your case I'd almost make a shared "Config.dll" library that would handle the config file.
~md5sum~

Is this on the service side or the client side? If on the service side, it is often the case that the service is running in its own AppDomain, so that if you set AppDomain.CurrentDomain.SetData(...) it won't apply to the service configuration.
I'm not entirely sure how to get around this, but you should be able to control the service's configuration by implementing your own ServiceHost.