Appsettings in .NET Core vs Webforms - .net-core

Question

I have a library which I use in both an ASP.NET app and a .NET Core app.
In both apps, I need to load settings from web.config(asp) in a virtual directory /CMSContent/Settings/web.config and appsettings.json(core).
I set an enviromentvariable in both apps named SystemType to WebForms(asp) and .NET Core (core), and build a function which reads data in the config file.
public static string SolutionDB()
{
string SystemType = System.Environment.GetEnvironmentVariable("SystemType", EnvironmentVariableTarget.Process);
switch (SystemType)
{
case "NetCore":
using (System.IO.StreamReader sr = new System.IO.StreamReader("appsettings.json", Encoding.UTF8))
{
var json = sr.ReadToEnd();
}
return "ComitoCMS_1";
case "WebForms":
System.Configuration.Configuration config = WebConfigurationManager.OpenWebConfiguration("/CMSContent/Settings/");
return config.AppSettings.Settings["SolutionDB"].Value;
break;
default:
return string.empty;
}
return string.empty;
}
When accessing the function from .net core it always returns the error:
TypeLoadException: Could not load type 'System.Web.Configuration.WebConfigurationManager' from assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
Even though the code doesn't get into the case "WebForms".
Is there any other way to read either web.config when running the asp.net app and from appsettings.json when running the .net core app

Answer 1

I would suggest to create library with an abstraction. For example ConfigurationValueProvider class.
public abstract class ConfigurationValueProvider
{
public abstract GetValue(string key);
}
Then create another two libvraries. One with implementation for .NET Core and second with implementation for WebForms.
NET Core
public class AppSettingsValueProvider : ConfigurationValueProvider
{
public override GetValue(string key)
{
// Load value for NET Core apps
}
}
WebForms
public class WebConfigValueProvider : ConfigurationValueProvider
{
public override GetValue(string key)
{
// Load value for WebForms apps
}
}
Each project type should reference just the one it is supposed to be used.
It is an idea how to do it. You should change it according to your needs.