- call a method in c# assembly (from powershell) which further refers to its own dependent assemblies - the dependent assembly reads some info from app.config (to display msg).

Math.cs

namespace SampleDotNetFullLib
{
    public class Math
    {
        public string GetMessage()
        {
            var o = new AnotherLib.Messages();
            return o.GetMessage("in Math.GetMessage");
        }

        public string GetSum(int a, int b)
        {
            var o = new AnotherLib.Messages();
            return o.GetMessage($"Sum = {a + b}");
        }
    }
}

Messages.cs

namespace AnotherLib
{
    public class Messages
    {
        public string GetMessage(string a)
        {
            var prefix = System.Configuration.ConfigurationManager.AppSettings["MsgPrefix"];
            return $"{prefix}: {a}";
        }
    }
}

sample.ps1

[System.AppDomain]::CurrentDomain.SetData("APP_CONFIG_FILE", $null)

Add-Type -AssemblyName System.Configuration
$config_path = "C:\temp\Powershell-DotNet-Samples\03\app.config"
[System.AppDomain]::CurrentDomain.SetData("APP_CONFIG_FILE", $config_path)
[Configuration.ConfigurationManager].GetField("s_initState", "NonPublic, Static").SetValue($null, 0)
[Configuration.ConfigurationManager].GetField("s_configSystem", "NonPublic, Static").SetValue($null, $null)
([Configuration.ConfigurationManager].Assembly.GetTypes() | where { $_.FullName -eq "System.Configuration.ClientConfigPaths" })[0].GetField("s_current", "NonPublic, Static").SetValue($null, $null)

[System.AppDomain]::CurrentDomain.GetData("APP_CONFIG_FILE")
[System.Configuration.ConfigurationManager]::AppSettings

#main assembly
[Reflection.Assembly]::LoadFrom("C:\temp\Powershell-DotNet-Samples\03\SampleDotNetFullLib\SampleDotNetFullLib\bin\Debug\SampleDotNetFullLib.dll")

$oMath = new-object -TypeName "SampleDotNetFullLib.Math"
Write-Output $oMath.GetMessage()
Write-Output $oMath.GetSum(10, 20)