What's the equivalent of the DictionaryAdapterFactory of Windsor in IHostBuilder?

Question

I am moving a console application from .NET 4.6 to .NET 5. At the same time the idea is to get rid of Castle.Windsor and start using the builtin Dependency Injection present in Microsoft.Extensions.

I will be honest. I am not used to either of them. The application has an IApplicationConfiguration that is a representation of what we need from the app.config file.

How do I translate it to IHostBuilder?

Thanks in advance

Answer 1

Right, after investigating this, I found a solution using reflection.

Here is an example:

using System;
using System.Reflection;
using System.Reflection.Emit;

namespace TestConsoleNet5
{
    public class Program
    {
        public static void Main()
        {
            AssemblyName aName = new AssemblyName("DynamicAssemblyExample");

            AssemblyBuilder ab =
                AssemblyBuilder.DefineDynamicAssembly(
                    aName,
                    AssemblyBuilderAccess.RunAndCollect);
            ModuleBuilder mb =
                ab.DefineDynamicModule(aName.Name + "Module");
            TypeBuilder tb = mb.DefineType(
                "MyDynamicType",
                 TypeAttributes.Public);

            BuildPropertyAndConstructor(tb, "This is a test");

            tb.AddInterfaceImplementation(typeof(ITest));
            var type = tb.CreateType();
            ITest test = Activator.CreateInstance(type) as ITest;
            Console.WriteLine(test.propTest);
        }

        private static void BuildPropertyAndConstructor(TypeBuilder typeBuilder, string defaultValue)
        {
            string propName = "propTest";
            FieldBuilder field = typeBuilder.DefineField("m" + propName, typeof(string), FieldAttributes.Private);
            PropertyBuilder propertyBuilder = typeBuilder.DefineProperty(propName, PropertyAttributes.None, typeof(string), null);

            MethodAttributes getSetAttr = MethodAttributes.Public |
                MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.Virtual;

            MethodBuilder getter = typeBuilder.DefineMethod("get_" + propName, getSetAttr, typeof(string), Type.EmptyTypes);

            ILGenerator getIL = getter.GetILGenerator();
            getIL.Emit(OpCodes.Ldstr, defaultValue);
            getIL.Emit(OpCodes.Ret);


            propertyBuilder.SetGetMethod(getter);
        }
    }
    public interface ITest
    {
        string propTest { get; }
    }
}

So, where you find "This is a test" you should pass the value from the config file.

Also the interface should be the IApplicationConfiguration

It is a bit messy but it works.