Intermezzo–options for loading multiple providers of data – part 10

We have 2 national banks –  and we gather exchange rates from there. What if we want to add more banks  -or let other programmers to add their dll’s to our software to just display the exchange rates from other banks ?

Option 1: HardCode all the list

var l = new List<IExchangeRates[]>
{
new GetFirstBank()),
new GetSecondBank()),

};

Option 2: Reading from some config file the list of classes – letting DevOps to modify the config file

var l = new List<IExchangeRates[]>;

foreach(var line in File.ReadAllLines(“myListOfExchangeRates.txt”){

IExchangeRates r= Activator.CreateInstance(Type.GetType(line)) as IExchangeRates ;

l.Add ( r );

}

Option 3: Reflection – in the current assembly or in all assemblies to load the classes that implements the interface to load the data

var typeToFound = typeof(IExchangeRates);
Assembly a = Assembly.GetExecutingAssembly();
var types = a.GetTypes()
.Where(it=>it.IsPublic)
.Where(it => it.GetInterface(typeToFound.FullName)!=null)
.ToArray();
foreach(var t in types)
{
recognizes.Add(Activator.CreateInstance(t)as  IExchangeRates);
}

Option4 Load as plugins

use the library from  https://github.com/natemcmaster/DotNetCorePlugins/blob/master/samples/hello-world/HostApp/Program.cs  and there are 2 lines,basically:

var loader = new LoadExchangeProviders("plugins");
var exchange = loader.LoadExchangeProviders().ToArray();